THE STRANGE DISAPPEARANCE OF JOE CARDONA by Maxwell Grant As originally published in "The Shadow Magazine," November 15, 1936. The weird purple death menace which The Shadow battles is but a prelude to a more amazing event - the Strange Disappearance of Joe Cardona! CHAPTER I THE PURPLE DEATH "LOOK at this, Cardona." Fiercely, Police Commissioner Ralph Weston brandished a newspaper before the eyes of his ace inspector, Joe Cardona. The headline, in a big-typed streamer, read: PURPLE DEATH STRIKES AGAIN His swarthy face grim, Cardona received the newspaper with tight-fisted hands. He grimaced when he noted that the newspaper had foregone the usual red ink that it used for sensational headlines. The big letters were printed in purple; the very hue that represented death itself. Cardona watched Commissioner Weston pace the floor. Weston seemed cramped for space, in this little office that was situated in his apartment. Cardona saw the commissioner pause and stare through the darkened window, where the rattle of an early winter sleet storm was clashing against the panes. Beyond were the lights of Manhattan, blurred by the sweeping sleet. The tops of skyscrapers were lost, enveloped by the swirl. The frown that showed on Weston's firm, square-jawed face was proof that the police commissioner was utterly befogged by the trend of recent crime. Cardona took another look at the newspaper. He saw a subhead in smaller type: Detective Missing After Finding Button Clue Cardona grunted. "These morning sheets work quick," commented the ace. "I didn't think they'd get the news of Doolan's disappearance in time for the bulldog edition." Weston swung about from the window. He said wearily, "Five deaths in three nights; four of our best men missing. Lacey, Kirk, Jenkins - now Doolan. What's become of them, Cardona?" Joe shook his head. Even his poker-faced countenance could not conceal the emotion that he felt. Murder was bad enough; the evanishment of every detective detailed to a case made the situation acute. "Five disconnected deaths," mused Weston. "An obscure mechanic, a university instructor, a radio announcer, a Wall Street promoter, a pawnbroker. None, apparently, ever knew the others. Four competent detectives missing. Two - Lacey and Kirk - gone before they learned anything. Two others - Jenkins and Doolan - vanished after delivering clues that have not helped us. "Jenkins found a fountain pen, significant only because it contained ordinary purple ink. Doolan found a common button from a shirt cuff; not the commonest sort of button, but one that is common enough. These clues may be valuable, should we find a suspect; but in themselves, the clues are useless." CARDONA pondered over Weston's words, then remarked: "Maybe the clues mean more than we think, commissioner. They were important enough for the man who's behind these deaths to snatch the detectives who found them." Weston shook his head. "I don't think so," he declared. "The perpetrator of the purple death is merely flaunting his power in our faces. He wants us to know that our efforts to unearth him will prove futile." Weston drove a heavy fist down upon his desk. This was characteristic of him. "Five men have died," announced Weston, "from the effects of some baffling poison that turns their bodies purple. We know that the poison is similar to known ones, but it coagulates the blood of the victims to such extent that we have been unable to learn the time at which death struck them. That fact, Cardona, has masked the murderer's movements." Cardona nodded, listening to facts that he already knew. Suddenly, however, he put a question: "What about those new types of blood tests, commissioner? The ones you mentioned yesterday?" "I have talked with three experts," returned Weston. "Only one believes that results are possible. He is Professor Kinsley Murkden. He has made a special study of chemical reactions in the blood stream. In fact, he has been delivering lectures on the subject." "Did Murkden make any tests for you?" "Yes. Using blood from the most recent victim. The test failed because the victim had been dead too long. Murkden believes that he could ascertain the exact time of death if he could make tests within twelve hours after a victim's death." "Perhaps he may have the chance." Weston glared, for the moment, at Cardona's utterance. Then he sank back in his chair, nodding soberly. "You may be right, Cardona," he declared, solemnly. "We may have to meet new murders. If they come, let us hope that we learn of them soon enough to take advantage of whatever aid Professor Murkden may give us." A minute of silence passed, disturbed only by the sweep and rattle of the outside sleet. At last, Weston spoke methodically, passing Cardona a sheaf of report sheets. "It is unfortunate, Cardona," he remarked, "that you were away on vacation when these deaths began. However, beginning with to-night, you will have full charge of investigation. These reports are copies of those supplied us by the missing detectives. They are quite sketchy. "You will, at least, learn something about the purple death itself, as the descriptions of the victims are quite detailed. I may say" - Weston seemed to shudder as he spoke - "that the horror of the purple death is something that can not be described with mere words. If you had seen the victims, as I have, you would understand that fact." Cardona received the duplicate reports. Rising, he donned a heavy overcoat. WHILE Cardona was tightening his overcoat collar, the telephone rang. Weston answered it; Cardona heard the commissioner's end of a brief conversation. "Hello..." Weston's brisk tone slackened. "Ah, good evening, Mrs. Tabor... Quite an agreeable surprise, to hear from you... Certainly, I shall be glad to do the favor... Yes, a message to Mr. Tabor, at his studio..." Weston wrote an address on a pad. Cardona saw the commissioner smile, as he added: "I understand... Yes, I shall detail a tactful man to the duty. I have such a man right here at present..." Hanging up the receiver, Weston chuckled. "There, Cardona," he declared, "is an example of how results can be obtained by going to the man higher up, no matter how slight a task is required. The Tabors are friends of mine; socially prominent persons who live on Long Island. "Frederick Tabor is an architect; he has a studio here in town, where he goes when he does not wish to be disturbed. Here is the address." Weston passed the memo to Cardona, added, "It is ten o'clock. Tabor promised to arrive home before that hour. Mrs. Tabor thinks that he has forgetfully remained at the studio. Since there is no telephone there, she called me and asked me to send some one to the studio to remind him." Cardona stared. Weston saw Cardona's gaze and chuckled anew. "It is making a messenger service out of the police department," admitted Weston. "However, the Tabors are important people. I assured Mrs. Tabor that I would send an experienced man who would not unduly alarm her absent-minded husband." Weston was still chuckling when Cardona left, but Joe was muttering to himself when he arrived outside the apartment house. Hailing a cab, Cardona gruffly gave his destination. Riding along, Cardona continued to fume. The ace inspector knew that the commissioner was actually using his office to curry favor. With all his efficiency, Weston had that one fault. And it antagonized Cardona. THE taxi stopped in front of an old building on a secluded side street. Alighting, Joe looked up at the darkened windows. He shrugged his shoulders, deciding that Tabor must have already gone home. But when Cardona turned about, his taxi was gone. The driver had received his fare, and had pulled away while Cardona was staring at the building. There was a small lunch room several doors away. Muffling his face against the slicing sleet, Cardona strode in that direction. Entering, he sat down at the counter, threw back his coat collar and ordered a cup of coffee. "I'm looking for an architect's studio," Cardona told the man behind the counter. "The fellow's name is Tabor. I thought maybe I'd picked the wrong building, because I didn't see any lights there." "You want Mr. Tabor?" returned the lunch room man. "You'll find him there, probably. His studio's on the third floor at the back. That's why you saw no lights. Mr. Tabor must be there. He didn't bring back his coffee cup." "His coffee cup?" "Yes. Every time he works at night, he comes here with a big thermos bottle. I fill it up with coffee and give him a cup with it. When he leaves the studio, he stops here to leave the cup." "He stopped for coffee here to-night?" "Yes. At eight o'clock." Cardona gulped his own coffee and left the lunch room. He entered Tabor's building, went up two flights of stairs that were lighted by a small incandescent on the second floor; a glow that had not been noticeable from the street. Reaching the third floor, Cardona saw a door that had a glass pane, illuminated by a light from the other side. On the door, was the lettering: FREDERICK TABOR ARCHITECT Cardona rapped lightly on the door. There was no response. Cardona rapped more loudly. Still, Tabor did not answer. Cardona shrugged. Probably, Tabor was working in an inner room and could not hear the knocks. Cardona tried the door. It opened. The inspector stepped into a little anteroom. There, he saw two chairs and a table, which supported a lamp. On the table Cardona observed the corked thermos bottle. Beside it was a cup that contained a half-inch of coffee. There was a door beyond, marked "Private." It apparently explained why Tabor had not heard the knocks. Joe rapped against the inner door. There was no response from the studio. Deciding that he had wasted enough time, Cardona opened the inner door. JOE'S first impression was one of complete disarray. The studio that he viewed was lighted only by a large lamp that stood in a corner, shining upon a table that supported a draftsman's board. A T-square, angles, protractors, drawing instruments and slide-rule, were lying on the floor. Beyond, Cardona saw the gaping front of a metal file cabinet, from which the drawers had been yanked and left on the floor. Papers and building plans were strewn on the floor. Scanning that area, Cardona spied a rack in a far corner, saw a coat hanging there. A man's still form showed bulkily on the darkened floor below. With a grim exclamation, Cardona sprang to the corner. Cardona knew that this hunched man who lay face downward must be the architect, Frederick Tabor. The man's dark trousers matched the coat upon the rack. Gripping Tabor's shoulders, Cardona rolled the man toward himself. Tabor's head tilted face upward. From past Cardona's shoulder came the revealing light. With a blurt, Cardona dropped the inert shoulders, let the body sag as he dropped back to stare. Frederick Tabor was stone dead. It was not that fact, however, that had appalled Joe Cardona. The ace inspector was accustomed to viewing death; he had guessed that Tabor was dead from the moment that he had begun to roll the body. It was sight of Tabor's face that made Cardona spring away as instinctively as if he had just escaped stepping on a rattlesnake. Never had Joe Cardona seen a face so contorted. Whatever handsomeness Tabor might have once possessed, his dead features showed no trace of it. Cheeks were puffy, swollen. Lips were twisted and bloated. Eyes were bulging orbs that looked like imitation chunks of glass, ready to drop from the sockets that held them. Below them was a nose, with wide-spread nostrils like those of a primitive savage. It was a feature that completely banished all semblance of a human countenance. Doom had left a mark that could never be erased, for it dominated every inch of Tabor's face. The dead man's visage was dyed a deep purple; a color deeper than a stain. That lurid hue seemed to have crept from within, to reach the outer flesh and tinge it with the evil dye. Hands, crossed on the dead man's chest, were puffed and purple. The penetrating stain had even purpled the finger nails. Cardona had learned the truth of Weston's words, the moment that he had viewed the dead face of Frederick Tabor. Embarked upon a seemingly unimportant errand, Joe Cardona had stepped squarely into the chain of crime that he had been ordered to investigate. The ace sleuth had found Frederick Tabor, the latest victim of the purple death! CHAPTER II CARDONA'S CLUE ONE hour later, Joe Cardona was standing in the center of Tabor's studio with an audience about him. In the group was a police surgeon and two grim-faced detectives; also the proprietor of the downstairs lunch room. Most important, however, were Ralph Weston and a man whom the police commissioner had brought with him. Weston's companion was Professor Kinsley Murkden, the blood expert who had expressed the belief that tests could solve the riddle of the purple death. Tall, stoop-shouldered and frail of build, Murkden was craning forward with one hand cupped to his ear. The professor was hard of hearing, but his keen eyes showed him to be alert. That fact had offset Cardona's disappointment at first meeting the professor. Joe's original impression was that Murkden was a deaf old dotard. He had changed that view after watching Murkden make a sharp visual survey of the entire studio. "I've made a thorough inspection, commissioner," announced Cardona, to Weston. "I'm ready to reconstruct the crime." "To begin with," continued Cardona, in a loud tone that brought a pleased nod from Murkden, "Tabor came up to this studio at eight o'clock. I arrived here soon after ten. So we know for a fact that he died between eight and ten. "The doctor here" - Joe waved toward the police surgeon - "has been unable to fix the time of death. That was to be expected. It's the way the purple death has worked before. However we both are agreed on how death was dealt. The murderer put poison in Tabor's coffee cup." Striding over to the door that led to the anteroom, Cardona pointed to the thermos bottle and the cup, which still stood on the outer table. He also indicated the hallway door. In loud tone, he continued: "Tabor came in here at eight o'clock. He set down the thermos bottle and the coffee cup. He left the door unlocked, came in here and went to work. Soon, he went out and had a cup of coffee. He left a little coffee in the cup. He came back to work again. "That's when the murderer moved in. Tabor didn't hear him, because Tabor was here in the studio. The murderer dropped a pill, or some other poison in the coffee cup. After a while, Tabor came out for another cup of coffee. The murderer was gone before that. "Tabor filled his coffee cup, took a long drink of it and came back to work. That's when the poison hit him. He collapsed. The murderer came in here and rifled the place. Figuring the whole job, I would say that be could have done it in about fifteen minutes." WESTON considered Cardona's summary; then put a sharp question: "The motive?" "To grab some plan that Tabor had," returned Cardona, promptly. "To cover whatever he took, he grabbed a lot of other things, too. That leaves us out of luck, commissioner." "There is another possibility," decided Weston. "The murderer may simply have rifled the place to make it look as though he sought some of Tabor's building plans." "Maybe," agreed Cardona, "but in either case, he's covered whatever he was after. It looks to me, commissioner, as though our first step is to get the time element straight." "Did you hear that, professor?" inquired Weston. "Do you think you can help us?" "I can," announced Murkden. "Especially if there is actually a trace of poison in the coffee cup." "We're sure of that," put in Cardona. "A purple color has shown up in the little coffee that we found there. But there's none in the thermos bottle That's how we know that the poison was put in the cup. The thermos bottle is less than half full. It looks clear." Professor Murkden raised his hand; waved a bony forefinger, as he stated: "I have already learned enough from previous cases to make tests with what we might term synthetic compounds, resembling this purple poison. A prompt analysis of the coffee will enable me to check my previous experiments. "More important, however, is the matter of fresh blood. My previous tests have been made too late to learn the exact rate of coagulation, which may be variable. If I begin to-night, with tests of this new victim's blood, I feel sure that I shall succeed in establishing the exact time of death." "Good," decided Weston. "The body is already on its way to our headquarters laboratory. Doctor, take Professor Murkden there. Detective Lewis will bring the coffee samples. We shall lose no time with this." Turning to Murkden, Weston made added query: "Tell me, professor, when can we count upon your first report?" Murkden considered, then replied: "To-morrow evening. Let us say after my usual lecture." "At what time do you lecture?" "From eight o'clock until nine." "Very well, professor. I shall call personally at nine o'clock." MURKDEN left with the surgeon and one of the detectives, who took along the thermos bottle and carried the coffee from the cup in a bottle that the police doctor provided. Cardona dismissed the lunch room proprietor, then turned to speak to Weston. He saw the commissioner staring at a partly opened skylight in the slanted ceiling of the studio. "What about that skylight?" demanded Weston. "Couldn't the murderer have come in that way, Cardona?" "No," replied Joe. "He would have had to go right through the studio while Tabor was working here. Besides, the skylight was locked when I examined it. Jammed so tight that I decided it hadn't been opened for months." "Why did you open it?" "I wasn't passing up anything, commissioner. I went out to take a look at the roof. I couldn't clamp the skylight afterward. I'd bent the bar opening it." "Mention all that in your report." Briskly, Weston marched about the room, studying strewn papers, looking in obscure corners. Joe and the detective watched him. Neither glanced again toward the skylight. There, motion occurred. The skylight inched upward. Solid blackness seemed to dominate the space, there was no influx of expected sleet. Gradually, the skylight lowered into place. Outside, a hidden watcher was on hand; some being whose ways were as impenetrable as those of night itself. A few minutes later, Weston finished his inspection. He turned to Cardona and queried. "What do you think of the time element? When would you say that Tabor died?" "I have no clue," returned Cardona. He paused, then added, "Only a hunch." "I though so," smiled Weston. "You always have hunches, Cardona. I used to ridicule them, but sometimes they proved good ones." "Thanks, commissioner," laughed Cardona. "Since you ask for it, I'd say that Tabor died at about half past eight." "Why?" "Because the murderer would naturally have tried to get him as soon as possible. Tabor drank one cup of coffee in the lunch room, at eight o'clock. Let's say he took the next at eight fifteen. The murderer had to wait until then to load the poison in the coffee that Tabor left. If Tabor took his next cup at eight thirty, that was when it finished him off." Weston mused over Cardona's statement. "Fifteen minute intervals," remarked the commissioner. "Not too short for a habitual coffee drinker. Perhaps you are right, Cardona." "What's more," added Joe, "if the killer knew that Tabor was due home at ten o'clock, he'd have planned to get him quick. Tabor would have had to leave here about nine thirty to get home at ten. Maybe he'd have gone before then. Maybe at nine." Weston nodded, impressed. Then, with a smile, he said: "This time, Cardona, your hunch will have opportunity to prove itself. I shall remember what you said and check it with Professor Murkden's test results to-morrow night." Cardona grimaced, knowing that his hunch would be criticized if proven incorrect. Cardona felt resentful. Ever since he had broken in as a detective, he had played his hunches. Yet Joe had never been able to convince the commissioner as to their accuracy. Weston saw that he had touched a sore spot. He tried to mollify Cardona as they went out through the anteroom. Clapping Joe on the back, Weston gave a grave reminder: "Don't forget what happened to the detectives on these cases, Cardona. You are too valuable a man to have disappear. I'm counting on you to smash the purple death." WITH that, Weston was gone, followed by the remaining detective. Cardona was closing the door between the studio and the anteroom. Slow footfalls on the stairs indicated that Weston expected Joe to join him below. For the moment, however, Cardona paused. A hunch had gripped him. "Clues," muttered Cardona, half-aloud. "That's why they've dropped out of sight. They picked up clues -" Joe had remembered the fountain pen found by Jenkins, the shirt button uncovered by Doolan. There was a chance that Kirk and Lacey might have discovered some items also. At least, it was certain that in the last two cases of the purple death, prior to Tabor's murder, some trace to the killer had been found. Why was there none here? Had the murderers been more careful, after reading of previous clues in the newspapers? As Cardona considered this factor, he stared across the anteroom. His gaze stopped upon a tiny object just within the door. Popping over, Joe picked up a square-shaped newspaper clipping. Unfolding it, he saw the diagram of a chessboard, with chessmen indicated on squares. Below the diagram was the statement: "White to Mate in three moves." Though Cardona was no chess player, he was familiar with the regular contents of most New York dailies; and there was only one newspaper - a morning one - in which he had seen daily chess problems. Noting the position at which the clipping had fallen, Cardona wondered if only the murderer could accidentally have dropped the clipping at that spot? Cardona hurried to the outer door. In the hallway, he stopped, the clipping still between his fingers. He could hear Weston's footsteps. With a grim smile, Cardona pocketed the clipping. Others had made the mistake of proclaiming their clues to the police commissioner. Weston, anxious to convince the newspapers that results were being gained, had let the news reach the press. But Cardona, for once, was decided on an independent policy. Dragged back from a vacation, thrown on to an assignment that promised danger, he felt that he was entitled to full leeway. Weston had offered him complete charge of the case; then had proceeded to crimp Cardona's favorite method of following hunches. Joe had made one mistake; that of revealing his first hunch. He did not intend to repeat it. His present hunch was that too much talk of the chess clipping clue would mean disaster. The best way to avoid such complication was to keep his find to himself. The clipping safely in his pocket, Joe Cardona closed the outer door of Tabor's studio and indulged in a satisfied smile as he started down the stairway to rejoin the awaiting police commissioner. So intent had Cardona been with his discovery that he had failed to notice any sound while he was still within the anteroom. Since Joe had closed the connecting door to the inner studio, it was no wonder that his ears had failed to hear the noise. The sound was a soft scrape from the skylight of the deserted studio. It was accompanied by an odd sight; the encroachment of solid blackness from above. The skylight had opened wider; the darkened mass that entered slowly molded itself into a human form. A swish followed as a tall shape dropped quietly to the floor. A tall stranger from the night stood in the studio where death had struck. Joe Cardona would have recognized that arrival, had he remained to witness this entrance. The tall being was cloaked in black. His hands were encased in thin black gloves; his face was obscured by the upturned collar of his cloak, the downturned brim of his black slouch hat. Yet from the space between the collar and the brim, eyes peered so keenly that their flash was visible. This being of blackness was The Shadow. Master crook who hunted men of crime, The Shadow, like the law, was on the trail of the purple death. With contacts everywhere, The Shadow invariably learned when crime was uncovered by the law. He had done so to-night. ARRIVING at Tabor's studio, The Shadow had passed policemen stationed outside while the commissioner was present. He had chosen his own route to reach the scene of crime; namely, by the roof. Finding the skylight that Cardona had opened, The Shadow had looked in and listened while Cardona had summarized the circumstances of Frederick Tabor's death. Men of the law had gone. It was The Shadow's turn to study the premises; to learn what other clues might be present. Conversant with Cardona's full report, The Shadow had gained a distinct advantage before beginning his search. Nevertheless, The Shadow had entered too late to peer into the anteroom in order to learn of Cardona's secret clue. A simple item, that clipped fragment of a newspaper; yet it could produce complications in the quest to learn the source of crime. Held by Cardona, that clipped chess problem promised trouble to its finder. Far better that The Shadow should have gained it; for he alone could have used the clue to full advantage. CHAPTER III BATTLE BY NIGHT THE search that The Shadow made through Tabor's studio was swift, yet detailed. The result, however, was negligible. Whoever had rifled this room had done the job swiftly, but with definite care to avoid any traces. Articles had been swept from Tabor's table. Files had been ripped from the cabinet. The Shadow granted that the murderer had worn gloves. Cardona had looked for finger prints, but had found none. Many of the papers from Tabor's files were gone. That was proven by The Shadow's discovery of architect's estimates that had missing pages. From this, The Shadow drew the definite conclusion that the murderer had actually wanted certain documents. A man faking a robbery would not have had to search for the items that he wanted; hence he could have bundled batches at random and strewn the rest about. The murderer, scattering papers, had been on the lookout for certain ones. Finding them, he had taken them; then snatched up groups of strewn papers. That was why some sheets of lengthy estimates had been left behind. This conclusion, however, was of little value. Tabor's papers were in chaos; obviously a large percentage of them were gone. There was no way to gain a lead to the particular type of documents that the murderer had purposely stolen. STEPPING to the outer anteroom, The Shadow studied the table where the thermos bottle and the cup had been. He saw a circled mark that indicated where the thermos had once stood on spilled liquid; to leave a stained ring in the woodwork. From the size of the circle, The Shadow decided that the thermos bottle had been a quart container. He recalled the statement that half the coffee was gone from it. Cardona had estimated that Tabor had finished two cups of coffee; one at eight fifteen, the next at eight thirty. Two cups, however, would not account for a missing pint. Even granting that Tabor drank coffee at fifteen minute intervals, The Shadow estimated that he would not have consumed a quart within an hour. Calculating on his own, The Shadow figured that the coffee clue would show that Tabor had died at about quarter past nine. Nevertheless, The Shadow made allowance for the possibility that Tabor might have drunk two or three cups at one sitting. Like Weston, The Shadow was willing to let the time element wait until after Professor Murkden had made his blood tests. Science - not speculation - offered the best solution to the evasive time element that invariably marked the purple death. While in the anteroom, The Shadow glanced at the spot where Cardona had found the clipped chess problem. The fact that The Shadow looked over the exact spot where the clue had been found was new proof that the murderer of Frederick Tabor had experienced real luck to-night. His search ended, The Shadow returned to the studio. He went up through the skylight, closed it exactly as he had found it. In darkness, he began a precarious course along the roof. Sleet had hardened into ice; moving along a frozen slant, The Shadow held his position in uncanny manner. His fingers and toes seemed to dig into a surface that offered no apparent security. The Shadow reached a projection of the roof; swung from its icy edge. This time, his fingers could not keep their clutch, but despite their slip, The Shadow gave himself an inward swing beneath the projection and landed on the platform of an old fire escape. Gripping the sleet-crusted rail, he descended toward a space at the rear of the building. Usually, The Shadow moved with absolute silence. To-night, that proved impossible. Steps in the fire tower were loose; The Shadow was forced to step heavily upon them, in order to gain a footing. The Shadow paused when he reached the hinged extension that formed the last six feet of the fire escape. Listening, The Shadow was rewarded for his caution. He heard sounds that were barely audible. Whispers that only his keen ears could have detected. No patrolmen, these. There were lurkers in the darkness just below; enemies who had somehow guessed the presence of The Shadow and had moved in during the time that he had been engaged in upstairs investigation. Those foemen had heard the slight clangs from the fire escape. Trouble might begin at any moment. The Shadow's position was a bad one; though the steps of the fire escape were iron, they were openwork and offered no bulwark. THE SHADOW did not hesitate. Rising on the rail beside him, he reached high and gripped a step above his head. Forcibly, he clanked the step; then the next one below it. The sounds, this time, were accurate. They gave a distinct token of the exact spots where they had occurred. The clanks, however, did not tell the most important fact; namely, that The Shadow was beneath the steps that clattered, not upon them. Stooping, The Shadow swung across the level rail of the lowest platform, ready for a six-foot vault to the area below. The Shadow was not an instant too soon. As his form swung from the rail, revolvers barked upward; simultaneously, big flashlights clicked their glare. The barrage that ripped the night came from half a dozen guns. Bullets found nothingness. Flashlights were luckier. As thugs fired uselessly, their companions with the lights gained a chance glance at blackness that was hurdling from the rim of their glowing circle. Harsh voices roared the fact that The Shadow had been spied. A clank marked The Shadow's thud upon the cement courtyard. It came from an automatic that he had whipped from beneath his cloak. Though half sprawled, The Shadow gained his feet, just as a flashlight swept in his direction. With quick aim, The Shadow boomed a shot for the thug who held the light. A sharp cry answered; the flashlight dropped from the thug's shattered hand. Revolvers ripped blindly. They were answered by new shots. A laugh of challenge accompanied the echoes of The Shadow's gun. Crooks were spurred to new fury. A sudden barrage opened from The Shadow's left. Though he had successfully shifted in the darkness The Shadow had not gained the stroke he needed. He had scoured this courtyard previously; had found it an open space that lacked cover. In the interim, the situation had changed. Crooks had brought their own entrenchments. The clang of bullets told that the thugs had carried in steel ash cans to serve as bulwarks. With the opening of The Shadow's fire, they had ducked for cover. Failing to locate The Shadow with chance shots, they were prepared to rake the whole area wherein he stood. Instantly, The Shadow remembered one spot that he had noted when first entering this courtyard. That was a broad basement window, in the building just behind the one that housed Tabor's studio. The low window was The Shadow's one chance of refuge, yet as he dived for it, he shifted. His hands found the wall beside the window. The Shadow dropped flat in the cement. Pot shots were whistling from ash cans. With brief whines, bullets were thudding walls. Slugs pounded above The Shadow's head; yet the cloaked fighter did not move. He was listening for sounds close by. He heard them, from the very window that he wanted. "HOLD the glim, Skeet," came a whispered tone. "Don't use no rod, neither." "Other guys are shootin'," was the response, in a low growl. "We got as much chanct of baggin' The Shadow as they have." "Yeah. But they're behind the ash cans. They're foxing him. Our job is to cover. Get ready to duck when you hear three quick shots." "I know. That means the typewriters. You told me that before, Jake." "I'm telling you again -" Metal swished through sleety darkness to end Jake's sentence. With short forearm stroke, The Shadow had sliced at downward angle through the opened window. His sledge blow was perfect, despite the darkness. The weight of a .45 automatic slumped Jake into temporary oblivion. "Skeet" heard the blow; uttered a snarl and jabbed his revolver through the window. Two arms drove through like pistons. Diving in from the night, The Shadow clutched Skeet's gun wrist with one fist; dropped his automatic to grip the thug's throat with the other. As the big .45 bumped the basement floor, two figures plunged upon it. One was Skeet, sprawling backward, to crack the stone flooring with the back of his skull. The other was The Shadow, his swift drive finished. He had plunged in from the night to gain this basement stronghold. As Skeet succumbed, there came three shots from the courtyard; their quick succession was a signal, delivered by an entrenched leader. An instant later, machine guns clattered from two entrances to the walled area. The "typewriters" were speaking, as Jake and Skeet had prophesied. Bullets streamed through the window, as the spraying machine guns raked every inch of the courtyard. Wisely had thugs been told to duck as soon as the triple signal was given. Otherwise, they would have been clipped in the thorough barrage that had been intended for The Shadow. Crouched below the window, The Shadow heard the drilling cease. He knew what was to follow. He bobbed up to the window, ready for it. LIGHTS flashed everywhere. Shouting their triumph, crooks leaped from their strongholds. They were as ready with the bull's-eye lanterns as they had been with their guns. Each wanted the first sight of The Shadow; all expected to see a cloaked figure sprawled by a courtyard wall. Instead, they viewed blankness. As they gaped, they heard a chilling sound. A burst of mocking laughter pealed from somewhere; most of the ruffians thought the challenge was delivered in their very midst. One man spied the window where Jake and Skeet had been on guard. He shouted, aimed with a revolver. The gesture was useless. Swinging away, The Shadow ducked low and crossed to the rear of the basement room. He blinked a tiny flashlight, saw a doorway and went through it. Ahead, he saw a flight of stairs up to the ground floor. He took that route. Out in the courtyard, crooks were firing from cover, speeding bullets through the open window that The Shadow had left. Their leader shouted a command; thugs rose en masse to drive across the court, firing as they came. They were sure that they had forced The Shadow to drop to cover; by closing in with their barrage, they hoped to smother him in his temporary stronghold. As the first attacker reached the center of the courtyard, a strident cry halted them. It came from above; not from below. Before the crooks could understand it, the laugh was followed by the blast of automatics, pumping downward from a high ground-floor window. The Shadow had gained a new position. He had caught his opponents flatfooted in the center of the courtyard. Their own guns had betrayed their positions. The crooks had but one choice. They scattered. No longer did they seek cover; they dashed for complete escape. They took to the passage that led to streets, their snarling leader running with them. Loaded, then reloaded, those automatics had done valiant work. Thugs were scattered; there was no need to pursue. Already, shots were sounding from outer streets. Patrolmen and police cars were closing into this neighborhood. Only the luckiest of the crooks could hope to evade that gathering cordon. Finding a side window, The Shadow dropped to a passage from the courtyard. He gained the night; took his own course, away from the shrill wail of sirens that marked the approach of the law. Driving sleet blotted the cloaked fighter's course. The Shadow was gone again, into the depths of night. Several hoodlums had been wounded. Fierce fray had produced one important discovery. Whoever the perpetrator of the purple death might be, he feared The Shadow. The killer had guessed that the black-cloaked sleuth might be on hand to-night. That was why he had tipped off hordes of crooks to the possibility of The Shadow's arrival. The hidden killer had counted on the fury of the underworld to dispose of The Shadow. The stroke had failed. The Shadow, his very path unknown, remained the master of darkness. Lone master who battled crime, The Shadow would continue to defy all odds in his campaign to end the scourge of the purple death. CHAPTER IV CROOKS GIVE CHALLENGE AT eight o'clock the next evening, Police Commissioner Weston was seated at a late dinner in the grillroom of the exclusive Cobalt Club. He had come here to escape being hounded by reporters. Influential persons knew that Frederick Tabor had been the commissioner's friend. Couldn't he, Weston, do something about the purple deaths, they asked. Newspapers assumed that new murders were due. Some tabloid journals had intimated that Tabor's death might have been a slap at Weston. That suggestion did not assure other friends of the commissioner. They felt that they, too, might be marked for death. The rules of the exclusive Cobalt Club forbade loud conversation among the members. Hence the commissioner had come here knowing that he could not be button-holed. Moreover, he had chosen an hour at which the grillroom would be nearly empty. Thus the commissioner had found the seclusion that he wanted. While glaring at the headlines of an evening newspaper, Weston noted blackness glide across the page. He looked up to see a tall, calm-faced personage clad in tuxedo. He recognized this person as Lamont Cranston, a millionaire globe-trotter who habituated the Cobalt Club. "Sit down, Cranston," invited Weston. "I wanted to talk to some one; and you're the only chap I know here who won't harp on the mistakes I've made. This purple death has made fanatics out of all my acquaintances." A quiet smile showed on the lips of Lamont Cranston. Seating himself, the arrival made calm query: "Are there any new developments, commissioner?" "None," replied Weston. "I expect some to-night, however. You probably read in the newspapers that we are making special blood tests to learn the exact hour of Tabor's death." Cranston nodded. "Professor Murkden is producing the analysis," continued Weston. "I am to see him at nine o'clock." "At his home on East Sixty-sixth Street?" "Yes. How do you happen to know the address, Cranston?" "A friend told me about Murkden's lectures. I had intended to join the group that attends them. I believe that knowledge of blood conditions would be valuable to me." "Of course. Well, then, Cranston, our meeting is fortunate. I am going to Murkden's shortly. You may accompany me and meet the professor." WESTON paused to pour cream on a baked apple; hence he did not notice the keen glow that showed in the eyes of Lamont Cranston. That momentary burn revealed a fact that Weston did not know. Those eyes were the same ones that had shone last night, from beneath the brim of a shading slouch hat. This personage who passed as Lamont Cranston, friend of the police commissioner, was none other than The Shadow. Purely by coincidence, Weston happened to note a headline in the newspaper. He mentioned it. "Last night," remarked the commissioner, "there was a gun fray outside the building where Tabor died. We rounded up several wounded crooks. None of them, however, knew anything concerning Tabor. When questioned, they stated that they had come to combat The Shadow." "Quite interesting, commissioner," inserted The Shadow, in the quiet tone of Cranston. "Apparently you no longer hold to the theory that The Shadow is a myth." "I thought that once," admitted Weston. "Afterward, I gained actual evidence of The Shadow's existence and the power that he possesses. My own life was saved by his timely intervention." "You believe, then, that The Shadow is investigating the purple death?" "Yes. Also, that the master murderer guessed it; and tipped off certain persons in the underworld. The purple killer hoped to eliminate The Shadow; but failed. However, we have learned nothing from the episode. We believe that the hoodlums were commanded by a crook called Slook Howdrey; but we doubt that he knows the actual perpetrator of the purple death." The Shadow's fixed smile was proof that he agreed with Weston; but the commissioner did not gain any significance from the slight curve of The Shadow's lips. Calling the waiter, the commissioner signed the check. Accompanied by The Shadow, who strolled in leisurely fashion, Weston stalked from the grillroom. Outside, the pair entered the commissioner's car. THE professor's residence was an old brownstone affair that squatted among decrepit buildings. Ascending the high steps, the visitors were admitted by a solemn-faced servant who ushered them into a large room. Entering quietly, Weston and The Shadow found a group of twenty persons listening while Murkden lectured from a small platform. Peering over the tops of bifocal spectacles, the stoop-shouldered professor recognized the commissioner and nodded affably; then resumed his lecture. A clock on the wall showed five minutes of nine when Murkden finished his lecture. The members of the group congregated to ask questions. Murkden answered them briefly. One by one, the questioners departed; in less than five minutes, all were gone. Murkden approached Weston and shook hands. The commissioner introduced the professor to The Shadow. Murkden's eyes showed interest when he learned that Lamont Cranston was a traveler. The professor remarked that he had made many tests with the venom of poisonous reptiles, including the cobra; that he would show his visitor charts that gave the percentages of fatalities among the victims of snake bites. Then, with a wan smile, the professor remembered that he had a more important duty; that which concerned his analysis of the purple death. Murkden unlocked a door at the back corner of the lecture room. Murkden led his visitors through a series of doors down to the basement. There, he unlocked another door and conducted them into a square room that was equipped like a laboratory. The windows of this room were covered with crisscrossed gratings; that was evidenced by one raised window. The panes of the windows were frosted; hence other gratings could not be seen beyond the closed sashes. The Shadow eyed the barriers; saw that while they were strong enough to offset ordinary prowlers, they would not tax an expert. The same applied to the locks on Murkden's doors. However, The Shadow made no comment. As Lamont Cranston, he was not supposed to be an authority who could criticize methods of anti-burglary protection. Furthermore, The Shadow had something more important to command his attention. Murkden had stopped at a table in the corner; there, the professor was indicating a row of glass beakers that bore various labels. He chose a beaker marked "F." HE said, "This beaker contains the equivalent of the poison that caused the purple death." Murkden briefly told them of his experiments. Then, laying the last tube aside, Murkden picked up a sheaf of papers and passed them to Weston. "These are the opinions of consulting chemists," declared the professor. "I called them in this afternoon. They checked my results; gave certified reports. You will see that all agree." While Weston was looking at the sheets, Murkden went to another corner. There, The Shadow saw a large crate well stocked with guinea pigs. Murkden stopped at a table; opened a small box and displayed three more of the rodents. All of these guinea pigs were dead. "I experimented with these," declared Murkden. "I gave each an injection of compound F. Each guinea pig died within five minutes. I performed the first experiment alone; I called in a physician to witness the second; and your own police surgeon was here for the last, just prior to my lecture. Here are their opinions." Weston had come to the corner. He received the new statements that Murkden gave him. "What are these references to microscopic slides?" queried Weston, reading the reports. "Do they concern the post mortem effects?" "Yes," replied Murkden. "Here are the slides. They show specimens of blood taken from guinea pigs at regular intervals after death." Producing a box of glass slides Murkden stepped to a projector and focused it upon a screen. Extinguishing the room's brighter lights, he inserted the first slide. Its microscopic details were projected on the screen. "The blood condition immediately after death," announced Murkden. "Note the slight coagulation that the poison instantly produced. This second slide" - he clicked another glass sheet into place - "shows greater coagulation. It has blood that was tested fifteen minutes later." In progression, Murkden inserted new slides, stating the time element as he displayed them. He called attention to the fact that the coagulation became more rapid with each interval. When he reached the slide that marked exactly three hours, Murkden paused and inserted a darker slide. "From the police laboratory," he announced. "A specimen of Tabor's blood, tested at precisely half past eleven last night. Its condition corresponds exactly with that of the guinea pig." "Then Tabor was dead three hours!" exclaimed Weston. "That places the time of his death at half past eight!" "It does," assured Murkden. "Look. Here are two more slides. Tabor's blood at twelve thirty; the guinea pig's blood at the end of four hours. They are identical." As further proof, Murkden inserted slides that showed the fourth and fifth hours. They corresponded. The next slides, showing six hours, scarcely differed from the ones before. "By six hours," explained Murkden, "the coagulation has lost its increasing ratio. It gradually continues, but with decreasing speed; until at twelve hours, it takes a final level. That is why fresh blood was needed to solve the riddle of the poison. Tabor's blood has enabled us to settle all facts for future reference." "Humph," muttered Weston, to The Shadow. "Cardona was right in his hunch. He told me last night that he believed eight thirty to be the time of Tabor's death." THE SHADOW made no comment. He, like Cardona, had made a conjecture that was partly guesswork. The Shadow's calculation had tended to show death at half past nine, an hour later than Cardona's. The blood tests, however, had shown Cardona's estimate to be correct. Because of this scientific evidence, The Shadow conceded that he had been wrong. The answer could be the long shot guess that The Shadow had not ignored; namely, that Tabor had drunk two or three cups of coffee in prompt succession. Finished with the slides, Murkden turned on the laboratory lights. Weston commended the professor's work, in a loud enough tone for Murkden to hear. The professor smiled at the commissioner's approval. He placed the certified reports in a large envelope and tendered them to Weston. Glancing at his watch, Weston noted that it was nearly quarter past nine. He suggested to The Shadow that they return to the Cobalt Club, as Cardona was due there shortly. Accompanied by Professor Murkden, they went upstairs and left by the front door. The commissioner's car was standing in front of the house, the chauffeur beside it. The chauffeur turned to open the door the moment that the commissioner appeared. Entering the limousine with The Shadow, Weston waited until the chauffeur had taken the wheel; then he gave a brisk order: "Cobalt Club, Larkin." The big car started. Simultaneously, the door on Weston's side swung open. The commissioner reached to grab it; at that instant, a figure sprang into the moving car. Timed to the same moment, a head bobbed up from the front seat, beside the chauffeur. A passing street lamp threw its glimmer on masked faces; below them, it showed the glitter of aimed revolvers. The man who had leaped in from the curb issued the growled order: "Stick 'em up!" Weston gaped as he stared into the masked man's leveled revolver. The Shadow, too, was eyeing a straight-aimed weapon. He was looking into the muzzle of the gun from the front seat. Crooks had sprung a daring trap. With sheer boldness, they had invaded the police commissioner's car, to cover its two occupants. Thuggish outlaws had captured Police Commissioner Weston; and with him they had bagged The Shadow! CHAPTER V THE SHADOW'S RIDE EVEN to The Shadow, the turn of events was sudden. The crooks had staged a clever coup. Nevertheless, their game would have failed had they tried to trap The Shadow alone. At the very instant when the first man arrived from the dark, The Shadow had shifted to the left. His hand had gone beneath his overcoat; it was gripping the handle of an automatic. One quick sweep of the wrist and The Shadow could have blasted the thug in the front seat, then gone for the fellow at the door. Circumstances made The Shadow halt. A life was at stake other than his own. As Weston's hands came up, The Shadow released his gun and copied the commissioner's move. Murder could not be the intent of these invaders; they would stir up unnecessary trouble if they slew the police commissioner. And to them, The Shadow was merely a companion of the police commissioner. The guise of Lamont Cranston was serving well. Weston was fuming as he faced the revolver just before his eyes. The Shadow merely settled back, his arms well raised, to observe what was due to follow. "Head for the park, Hunk," rasped the leader who had entered the rear of the car. "Take your time so Jerry can tail us; and pick some places where there ain't much traffic. I want to talk to the commissioner." For the first time, Weston realized that the chauffeur was not Larkin. Another thought struck him, also. The masked leader of this tribe must be "Slook" Howdrey, the crook who had sought The Shadow's death last night. Unwisely, Weston blurted his guess: "You're Slook Howdrey -" For an instant, The Shadow saw a finger tighten on its trigger. At that grim instant there was no chance to save the commissioner's life. Weston's own blunder had placed him at the mercy of a killer. Slook, himself, was on the point of signing his own death warrant with that of the commissioner. Had Slook tugged the trigger, he would not have lived long to enjoy his triumph. The Shadow was ready for a quick leap; a swift draw; a speedy bullet that would serve as vengeance in the event of Weston's death. Fortunately, the need of such action passed. SLOOK'S finger relaxed. A snarl came from the crook's mask. Slook had decided to defer Weston's death; partly with the hope that it might not prove necessary. "Sure," he growled. "I'm Slook Howdrey. I'm lamming out of town to-night, savvy? But before I lam, I want to know what the old prof spilled to-night. About those blood tests he was making." The car had reached Central Park. The Shadow, gazing toward the mirror, could see the headlights of another car that was covering the commissioner's. Again, The Shadow counted upon Weston to use discretion. He believed that the commissioner had recognized his previous blunder and would not commit another. "The tests," spoke Weston, slowly, "were not conclusive. I learned nothing of consequence from Professor Murkden to-night." Weston managed to put the falsehood in a deliberate tone. For the moment, it seemed to satisfy Slook. Then the killer snarled: "Nothing important, eh? What about that envelope you were shoving in your pocket when you came out the door?" "It contains reports of the tests -" "Shove it over. Easy does it. Reach for a rod and I'll drill you." Gingerly, Weston drew the big envelope from his coat pocket and extended it to Slook. A park light enabled The Shadow to see the strained look on Weston's face. The commissioner knew that if Slook examined the contents of the envelope the bluff would be known. The Shadow, however, hoped that Slook would inspect the envelope. By so doing, Slook would relax his vigilance, thus giving The Shadow opportunity for action without danger to Weston. "Let me explain the contents of the envelope." Weston, expecting trouble, was trying to make ready for it. "The papers that you will find there are actual reports of tests, but they represent the opinions of different persons. No one alone could vouch for all the statements." "Maybe you could." "Hardly." Weston was quick with his comment. "I merely glanced at the reports." "Does the prof have duplicates?" "No. These are the only ones." "He can make new tests, though." "That would be impossible. Frederick Tabor has been dead too long." Slook grunted in pleased fashion. He spoke to the thug at the wheel: "Pull up somewhere." THE big car rolled along a quarter mile, then turned into the entrance of a deserted bridle path and halted. "Hunk" clicked off all the lights except the dash. Its feeble glow barely showed the masked faces of Slook and his two followers. Half a minute later, the following car pulled up in back of Weston's. Its lights went out. Slook chuckled his satisfaction at the closeness of the cover-up crew. "Listen, commish," began Slook, in a cold, harsh tone. "I'm telling you some straight facts. Savvy? I had nothing to do with croaking Tabor, or any of the other lugs that were wiped out by the purple death. I got into this last night, on a tip-off that I could get The Shadow, if I was smart enough. "That's why I showed up outside of Tabor's. The dope about The Shadow was the McCoy. He was there, right enough, but we didn't get him. To-day, like yesterday, I get another telephone call. From the same guy that wised me about The Shadow - a gazebo with a funny, drawly voice. He said he was sorry I missed out on The Shadow. Told me he'd sweeten things by handing me ten grand, if I'd take on an easy job to-night. "The job was to snatch you, outside of Prof. Murkden's. The guy in back of these purple deaths is wise that the prof knows this blood test business. I told the guy on the telephone to show me the ten grand. He said it'd be delivered to my hide-out and it was. That's why I'm on the job to-night." Slook paused, as if expecting comment from Weston. None came. After silence that was broken only by the throb of distant traffic, Slook added: "You wised to who I was. If you weren't the police commissioner, I'd have given you the works. But I got what I wanted - the envelope the prof handed you. Shall we call it quits?" This time Weston responded. His voice was as cold as Slook's. "Go on," suggested Weston. "Just what do you propose?" "I'm leaving you here," returned Slook, "tied up along with your friend. I'm lamming with the outfit. We'll leave word somewhere, so you'll be picked up in a couple of hours; and your chauffeur can be pulled out of the alley. That's where we left him. "But you're making a promise first - your word that you and this friend of yours will forget just one thing; that Slook Howdrey was the guy who snatched you. I wouldn't chance that with any dick, not even a guy like Cardona - they're double-crossers, all of 'em. But you and this mug with you are a couple of stuffed shirts; the kind that are dumb enough to stick to their word. "Even if you are the police commissioner, I know you'll go through with whatever you promise. I'm giving you an out. What's your answer?" COLD silence followed. Weston was considering Slook's statement. Thick darkness seemed to envelop the car. Amid the gloom, The Shadow's arms moved slowly downward. His ungloved hands were doubled; they were almost out of sight in the sleeves of his overcoat. "You are right," announced Weston, suddenly, to Slook. "My word, once given, would be kept. Nevertheless, I am not free to give such a promise. My oath to the law prevents me from declaring any truce with criminals." Slook edged closer to the commissioner. "Then you're figuring on a break," growled the killer. "Hoping that when we use the gats, some coppers will hear it. Hero stuff, eh? I'll show you how little it'll get you." The Shadow's hands were on a level with his shoulders, their downward drop still unnoticed by the crook who covered him. That thug was still ready with his revolver. So was Hunk. The driver had turned from the wheel and pulled a gun. But both were waiting for Slook's move. The Shadow's silence had given the impression that the only opposition would come from Weston. They were set to back Slook when he handled the commissioner. "Here's how I dish it." Growling the words, Slook shoved his face close to Weston's. The Shadow caught the side glimmer of a revolver; knew instantly what was coming. The Shadow's slow motion ceased, his hand shot to his overcoat. With a sudden side jab of his arm, he elbowed Weston squarely in the ribs, sent the commissioner sprawling against the wall of the car. The move was timely. Slook's creeping hand had already gone into a vicious swing; the revolver was driving for the base of Weston's skull. One blow there would have finished the commissioner. The sprawl saved Weston. Instead of taking the crash at the back of his brain, he received a glancing stroke upon the top of his head. Weston's hat broke the force; nevertheless, the whack stunned the commissioner. The Shadow had counted on it doing so. Weston, crumpling to the ample floor of the limousine, was out of the path of combat. His elbow serving as a pivot when it struck Weston's ribs, The Shadow's forearm snapped forward, straight in the direction of the front seat thug who covered him. With the swing, The Shadow pressed the trigger. His .45 roared within the confines of the car. The bullet found its target before the crook could fire. The dashlight's glow showed a head drop from sight in the front seat. As his arm recoiled, The Shadow rolled to the side, over Weston's slipping form. His quick move brought him under Slook's guard; for the killer had lost his balance when his gun had glanced from Weston's skull. Instantly, The Shadow and Slook were in a grapple. Hunk's raucous shout came while The Shadow's shot still echoed. To Hunk, the grapple was confusion. He could not distinguish The Shadow from Slook. Hunk jabbed his free hand for a button at the side of the car, pressed the switch to illuminate the dome light. The glow came on. Hunk aimed. He saw the face of The Shadow; that masklike visage that represented Lamont Cranston. It was showing above Slook's shoulder, a perfect target for close range. But Hunk, in that gloating sight, did not spot the dark automatic muzzle that tilted upward beneath Slook's arm. As he steadied to do sure work with his trigger, Hunk was greeted by a cannonlike roar that issued from the muzzle. Again, The Shadow had dispatched a timely blast. The blinding spurt of flame was the final impression of Hunk's life. With it came a bullet that found the thug's brain. Slook Howdrey wrenched free as Hunk fell. Hurling The Shadow half across the car, Slook jabbed his revolver for his foeman's heart. The Shadow's gun arm was wide, but his free hand hooked the handle of the door. With Slook driving down upon him, The Shadow yanked. The door swung under the double weight. Sprawling, two figures hurtled to the dried grass beside the bridle path. Slook's trigger finger tugged, but The Shadow's body was no longer at the muzzle. Bullets dug the ground. As Slook rolled over, wildly seeking new aim, The Shadow came up on one elbow and gave his third quick shot. Slook flopped to the earth. FIRST shots had not aroused the thugs in the other car. They had expected death in the limousine. The opening door made them think that Slook and the others were jumping out to join them. Their inkling of trouble came when The Shadow opened fire in their direction. Fortunately for the thugs, The Shadow had struck hard. Luckily, too, for them, he had carried along but one automatic on an expedition that had promised no great chance of battle. The inside pocket of Cranston's tuxedo jacket was not as ample a stowing place as the spaces beneath The Shadow's own cloak. The bullets that The Shadow drilled toward the thug-manned car were wide as the machine backed suddenly to the road. Jolted by his fall, The Shadow fired hazily at this longer range. As the car started away, The Shadow sprang between the trees, to avoid shots that were spurting in reply. Swinging out, he fired a last shot as the car came toward him. The driver had dropped almost prone; the bullet skimmed a half inch above his head. The car jolted, skidded in the ditch. As it righted, a thug leaned out, saw the white of The Shadow's tuxedo shirt and aimed with a revolver. Already The Shadow's arm was on its way. His automatic came flinging from the dark to crash the would-be killer's skull. The crook slumped. The Shadow's gun clattered beside him, a trophy to which the crooks were welcome, as it had served as well as a bullet. An instant later, the car was roaring through the darkness, its driver up at the wheel counting upon flight as the only sure policy. Only one of those departing crooks had seen The Shadow. That thug would not remember it. He was the one who had taken the hard-flung .45, from only eight feet distant. Central Park was well patrolled. Already, whistles were blowing; the chug of motor cycles could be heard. Mounted police were heading for the scene of gunfire. Quickly, The Shadow hurried back to Weston's limousine. He saw the one-eyed glare of motor-cycle headlights rounding into the bridle path. Diving aboard the car, The Shadow rolled beyond Weston, who was still on the floor. Finding the far door he slumped beside it; and became as silent as the other figures that occupied the limousine. When police arrived half a minute later, they stumbled over the dead form of Slook Howdrey; then discovered the bodies of Hunk and the other thug in front. A moment later, a patrolman saw a stirring figure; and dragged the groggy police commissioner from the limousine. Barely recovered, Weston stared dizzily into the glow of flashlights; then looked anxiously to the interior of the car. He smiled in relief as he saw policemen bringing out the slumped, but moving, figure of Lamont Cranston. Weston was pleased because his companion had also been saved from death. Not for a moment did he suspect that it was the supposed Lamont Cranston who had waged battle as The Shadow! CHAPTER VI CRIME STALKS ANEW "IT was The Shadow who rescued us, Cranston." Commissioner Weston was firm in his announcement as he and The Shadow rode southward through Central Park. The two were seated in the rear of a large sedan that police had commandeered in place of Weston's blood-spattered limousine. The Shadow made no comment. He smiled in the darkness. He knew that Weston had experienced the usual mental lapse that follows a hard blow on the head. The commissioner's recollection would remain blank concerning the quick action that The Shadow had delivered at the moment of Slook's vicious swing. As they reached Fifty-ninth Street, Weston glanced at his watch; noted that it was not quite ten o'clock. Not much more than half an hour had passed since the departure from Murkden's. That fact satisfied Weston immensely. "By this time," he announced, "officers whom I sent to Murkden's will be there. If any attempt is intended against the professor's life, they will protect him. I feel convinced, however, that such a possibility has been completely thwarted. If the purple killer - whoever he is - planned harm for Professor Murkden, the job would probably have been delegated to Slook Howdrey. "Moreover, the killer must have believed that he would accomplish enough results by dealing with me alone. Slook's warning was intended to make me drop the investigation of the purple death. Thanks to The Shadow, the law's work can proceed." As he finished speaking, Weston tapped the envelope that contained the reports on the purple poison and the blood tests. That valuable packet had been reclaimed from the floor of the limousine, where Slook had dropped it. The sedan pulled up in front of the Cobalt Club. Entering there, Weston made a prompt call to Murkden's. He chuckled as he talked across the wire; finished the call and turned to The Shadow. "The professor is safe," stated Weston. "He was asleep when the officers arrived, but the servants aroused him and he learned of our experience. The news quite bewildered him. I assured him that all was well; that I had instructed men to guard his house." An attendant interrupted to announce that the commissioner was wanted on the telephone. Weston answered the call. His face showed immediate alarm. Without a word, Weston motioned to The Shadow, then started from the club. They entered a taxicab. Weston gave an address on East Fifty-eighth Street. He told the driver to hurry. "Grave developments, Cranston," was Weston's only comment as they rode along. "That call was from Inspector Cardona." There was a grimness to the air of secrecy that Weston had adopted. Keeping to the role of Cranston, The Shadow leisurely lighted a cigarette and gazed languidly from the cab window. The taxi reached Fifty-eighth Street; slackened speed in front of a row of pretentious houses. JOE CARDONA was standing on the front steps of a house when the cab stopped there. He greeted the commissioner, nodded to The Shadow, whom he, like the commissioner, knew as Cranston. "This is Rythe's house," announced Cardona, to the commissioner. "I was called here at ten o'clock." "Trumbull Rythe," explained Weston, to The Shadow. "You've heard of him, Cranston. Rythe gained great wealth through his financial transactions. Always eccentric; but a remarkable financier." Weston's tone was tinged with gloom that indicated he was speaking of the dead. That did not surprise The Shadow. From the very beginning of the hurried ride, he had anticipated that the conclusion of the journey would bring them to a scene of crime. Cardona conducted the arrivals into the house, ushered them into a front parlor. There they found a long-limbed man in evening clothes, who was seated on a divan. The man's head was bowed. As the visitors entered, he looked up to reveal a sallow, pointed face. The Shadow saw the man wince at sight of Weston. He also caught the quick blink of evasive eyes. "Courtney Grell" exclaimed the commissioner. "What are you doing here? Is this man a suspect, Cardona?" "Please, commissioner," began Grell. "Don't accuse me -" "I made no accusation," interrupted Weston. "I asked a question. Let me tell you once again, Grell, your shady stock transactions can not be tolerated. On your last visit to my office, I gave my final warning." "I took it, commissioner," pleaded Grell. "I told you that I was through." "Yet I find you here -" "Because I sought to help the law." Grell's tone carried weight. Weston showed surprise; then looked to Cardona. The ace nodded. "That's correct. Grell phoned me," declared Cardona. "That's why I wanted you to hear his story first, commissioner." Weston looked mollified. He turned to Grell, expecting the man to speak. Instead, Grell trembled; his eyes shone wildly. Cardona whacked him on the back. Grell steadied. Rising, the long-limbed man went shakily to a cabinet in the corner of the room, where he helped himself to a drink from a decanter. "Guess it jolted him pretty bad, what he saw upstairs," confided Cardona, to Weston. Grell had steadied by the wall. Turning to Weston, the sharp-faced man began his story, in a voice that shook with occasional tremolo. "Trumbull Rythe understood me," declared Grell. "He knew that I sold good propositions along with bad ones. I always dealt on the level with him." "Reserving your fake transactions for dupes," put in Weston, sourly. Grell winced. "I called Rythe at eight to-night," resumed Grell. "His servant, Timothy, answered; told me that I could call at ten. When I rang the doorbell, Timothy did not answer. I found the door unlocked and entered. "No one was on the ground floor. I went upstairs. The door to Rythe's den was ajar, so I looked into the room. I saw" - Grell faltered, then fairly shrieked - "I saw Rythe!" As he gave the utterance, Grell stared toward the floor as though visualizing some horrible sight. He flung his hands in front of his eyes, staggered to the divan and sagged there. Cardona motioned to a detective to stay with Grell. Cardona led the way upstairs. INSTEAD of conducting Weston and The Shadow to Rythe's den, Cardona pointed to a front room. They entered to find a stocky, somber-faced man who was seated in a chair, staring moodily. The Shadow knew that this must be Timothy, the servant. "Hello, Timothy," spoke Cardona, in an assuring tone. "Here is the commissioner. Tell him what you told me." "There isn't much to say, sir," announced Timothy, sadly. "Mr. Rythe was upstairs in his den. I was reading in the kitchen. I chanced to remember that I had left the front door unlatched. I came to the front hall. I noted that the light was out. "I heard a stir from the stairs; I called to Mr. Rythe; he did not answer. I started upstairs in the darkness. When I reached the top step, something clapped upon my face. It was rubbery, like a sponge. Its odor overcame me." "Chloroform," explained Cardona. "Whoever used it stowed Timothy here in the front room. Tied him with those curtain cords; gagged him with his own handkerchief." Cardona pointed to exhibits that lay in a corner of the room. "At what time did this happen, Timothy?" The question came from Weston. The servant shook his head. "I don't know, sir," he declared. "The kitchen clock was stopped. All that I can say is that the time was somewhere between half past eight and half past nine." "You did not recognize your assailant?" "I had no chance, commissioner." Weston turned to Cardona. The inspector led the way to Rythe's den. They entered the little room to find the very sight that The Shadow expected. On the floor lay Trumbull Rythe, a huge, portly man who had crumpled crazily with his fall. He was clad in trousers and shirt that had no collar. All eyes were directed upon the dead man's face. It was a bloated countenance; large enough in life, hugely increased by death. Lips were pudgy; nose was swollen; eyes were goggly. Dyed deep in the dead visage was the fateful purple that told the cause of Rythe's sudden death. The purple death had taken a new victim, as terribly as it had struck down Frederick Tabor and others before him. CARDONA pointed to a couch. "Rythe could have been lying there," declared Joe, "or he could have been standing over near the wall. Anyway, the murderer didn't give him a chance. I can tell you how he killed him, commissioner." Cardona ran his finger along paneled woodwork, showed that it glistened with some sticky substance. Looking at the wall, Weston noted stickiness throughout the corner; even on the plush of the couch, although there it barely fringed the edges. "A spray gun!" exclaimed Weston. "The murderer administered a vaporized poison, like one would spray insects." Cardona nodded. "What's more, commissioner," affirmed the ace, "I'll tell you when it happened. At half past eight!" "How do you know that?" "On a hunch. Timothy says that some time between eight-thirty and nine-thirty, he came from the kitchen. Let's say that it was nine o'clock. What did Timothy do first? He called for Rythe, but there was no answer. "That shows Rythe was dead. The murderer was on his way out. He must have killed Rythe along about eight-thirty; then torn up the place." Cardona pointed to tables and a desk, from which the drawers had been removed. As at Tabor's, there were scattered papers. "Naturally, he would have made a quick get-away, after putting Timothy out of the way." Weston nodded his agreement; then recalled that he was endorsing one of Cardona's hunches. The commissioner chewed his lips, looked to the person nearest him, namely The Shadow. "What do you think of Cardona's theory?" queried Weston. "Do you agree with us that Rythe must have died at half past eight?" Weston stressed the word "us" as a sop to Cardona, but he wanted to thrust the burden of final agreement upon some other person. Weston expected The Shadow to agree. "We may presume," remarked The Shadow, "that Rythe was asleep upon the couch when the murderer entered. With the door closed, he would not have heard Timothy's call; but the murderer would have. The fact that the murderer waited for Timothy and disposed of him could indicate that he had not started his crime." THE SHADOW'S disagreement with Cardona's hunch pleased Weston. He liked the logic of this new theory. "Timothy was reading in the kitchen," added The Shadow. "Time would have passed more rapidly than he supposed. We might place the time of the murderer's entry later, on that account. Let us say at about half past nine." "Good reasoning, Cranston," approved Weston. "You have a rival, Cardona, in the matter of hunches. You say that Rythe was killed at eight-thirty; Mr. Cranston argues - quite as logically - that Rythe was slain an hour later." "Either could be correct," remarked The Shadow. "Perhaps, commissioner, it would be best to await the new blood tests that you will certainly have Professor Murkden make." "Of course," nodded Weston, his face looking sour. "We shall send the body to Murkden's at once, with a surgeon in charge of it. I meant to tell you Cardona" - Weston turned to the inspector - "that Murkden obtained results from his tests on Tabor's blood. He learned the hour of Tabor's death last night." "What time was it?" "At half past eight." The Shadow smiled as he saw Cardona repress a grin. Commissioner Weston finished up briskly. He ordered Cardona to attend to all details. That done, Weston departed with The Shadow. On the way out, they passed Courtney Grell, sitting glumly in the lower parlor. Outside, The Shadow parted from the commissioner and hailed a cab of his own. Riding toward Times Square, The Shadow sat immobile. His eyes, staring fixedly from the window, caught the glitter of passing lights. Those keen eyes showed a burning sparkle that did not change. In the purple death, The Shadow had encountered crime more subtle, more baffling than any of its sort that he had met before. He was planning a new campaign - one that would cover every possible detail - in his effort to solve the riddle of the purple death. CHAPTER VII THE SECOND CLUE A CURIOUS clock showed the hour of five. That clock was a singular arrangement of dials, set in concentric circles; three different rings for minutes, hours and seconds. The clock was revealed beneath the glow of a blue-rayed lamp. Everywhere else was darkness. Hands were moving across the polished surface of a table, beneath the bluish glare. They were the hands of The Shadow; long-fingered, tapered, busied with many tasks. Upon the table lay a map of Manhattan; typed report sheets; filing cards that listed names. The right hand held a fountain pen; it was making inked notations on a blank sheet. The Shadow was in his sanctum, a hidden room of darkness, somewhere in Manhattan. Night had passed; day had followed. Still, The Shadow was at work. The master sleuth had gleaned many details both in and out of his headquarters. As Cranston, he had received a call from Weston, during a short stop for lunch at the Cobalt Club. The commissioner had heard the results of Professor Murkden's new tests. Specimens of Rythe's blood had been tested as thoroughly as Tabor's; they had been matched by new experiments with guinea pigs. Again, Joe Cardona had been supported in his hunch. The tests proved conclusively that Trumbull Rythe had died at half past eight. This backed Cardona's theory that the killer had been on the way out when he encountered Timothy, the butler. Twice, therefore, The Shadow's own theories had proven wrong. That was not disturbing; in both instances, The Shadow had conceded that circumstances might not fit his conjectures. Nevertheless, it seemed certain that some unusual element was present in the chain of purple crimes. To trace it, The Shadow was using many measures. He had delved deeply into possible motives behind the deaths. Typed report sheets, culled from various sources, listed the various victims of the purple scourge. What could be the connection between such persons as a mechanic, a university instructor, a radio announcer, a promoter, a pawnbroker, an architect and a financier? The last two victims - Tabor and Rythe - had added to the chaotic situation. Nothing in all The Shadow's reports showed connection between any victims. The answer, as The Shadow saw it, must be an interwoven chain. All depended on a missing link - the murderer. Some supercrook was after great wealth. He must have gained control of something valuable. To hold it, he had murdered men who might have blocked his path. Some may have died purely because they could reveal facts later, when the killer's schemes reached the public eye. Others, The Shadow was sure, had died for different reasons, as yet unknown. Behind the purple death lay subtle strategy; the scheming of a mighty brain. The Shadow was sure that seizure of papers had been necessary at Tabor's, but not at Rythe's. This added to the problems that blocked The Shadow's progress. DROPPING the question of the victims, The Shadow considered other factors. First, Slook Howdrey. The Shadow dealt but briefly with the thug whom he had eliminated the night before. Slook was nothing more than a pawn that the purple killer had moved across the board. Once, to trap The Shadow; again, to cow the police commissioner. Slook had failed to interfere with either The Shadow's investigation, or that of the law. Second was Courtney Grell. Last night, Grell had chanced upon a scene of crime. Had that been purely by coincidence, or had the purple killer expected Grell to arrive at Rythe's? Considering these probabilities, The Shadow saw little choice between them. He doubted that either would matter. More important was the possibility that Grell knew who the murderer was. Grell, himself, was a shady character, the sort who would serve a master crook. That fact, however, made it seem unlikely that the murderer would employ him for so grueling a service as the discovery of a victim; unless Grell happened to be far more clever than appearances showed. The Shadow had not forgotten Grell. He intended to consider the fellow later. For the moment, however, The Shadow was concerned with another important person; namely, Joe Cardona. Until Cardona had taken charge of investigation, no victim of the purple death had been found soon after murder. That had changed with Joe's entry. Moreover, no theories had been offered concerning the times at which victims had died, until Cardona put them. He had guessed eight-thirty for both Tabor and Rythe. Professor Murkden's certified blood tests had proven Cardona right. In addition, there was another element. Every detective covering the purple deaths had vanished, until Cardona had stepped on the scene. Nothing had happened to Cardona. What was the answer? The Shadow had one. Astonishing though it was, the answer fitted. Joe Cardona, despite his efficient work, might actually be falling in line with what the murderer wanted. If that chanced to be the case, it explained why Cardona was still at large. Clues intrigued The Shadow. Other detectives had found them: a fountain pen and a button. There was a possibility that Cardona had uncovered clues but had kept them to himself. The Shadow intended to investigate that matter. The Shadow's clock showed quarter past five. Long fingers lifted a sheet of paper that bore the notation: Cardona. 5:30 p.m. Channing 5-3827. This brief report was from Clyde Burke, one of The Shadow's agents who posed as a newspaper reporter. Visiting headquarters, Clyde had heard Cardona making an appointment for half past five. He had noted the number that Cardona dialed. It was Channing 5-3827. The Shadow had checked on the telephone number. It belonged to a suite of offices, numbered 650, in the Landis Building, near Times Square. That suite was occupied by Courtney Grell. The Shadow's light clicked off. A whispered laugh sounded amid total darkness. The Shadow was ready for departure; from the sanctum, he would travel to the office in question. Arrival there at five-thirty would enable him to observe two persons: Grell and Cardona. Both were individuals upon whom The Shadow must concentrate. A conference between them promised real results. ANOTHER storm was sweeping Manhattan. Even at this early hour, the city was blanketed with night. Striving street lamps produced illumination amid a driving swirl of mingled sleet and snow; but above, the sky was as black as the Stygian depths of The Shadow's sanctum. Glittering windows, etched against night's velvet, indicated the lighted offices where late workers still lingered after the five-o'clock hour. One skyscraper that showed its quota of illumination was the Landis Building. Five-thirty showed crowds in the lobby of the Landis Building; for it afforded entrance to a subway and the rush hour was still strong. Among those passers appeared a tall stroller who carried a well-packed brief case. The Shadow had arrived at the hour of Cardona's appointment with Grell. Seven minutes later, Cardona himself appeared from the street and went up to Grell's suite. Joe entered without knocking. The shady speculator smiled wanly as he arose to shake hands with Cardona. Joe doffed his overcoat, thwacked a newspaper upon the table. Grell noted the folded journal; saw a conspicuous automobile advertisement showing from the uppermost page. He recognized it as a morning newspaper; wondered why Cardona was carrying it instead of an evening one. Cardona must have noted Grell's glance, for he immediately picked up the newspaper and stowed it in a pocket of his overcoat. Seating himself across from Grell, Cardona delivered a gruff opening: "You wanted to talk to me. All right. I'm here." "I appreciate the visit," acknowledged Grell. "You see, although you have not arrested me, I feel that you suspect me in the matter of Rythe's death." "What gave you that idea?" "Ever since last night," replied Grell, "I have noted headquarters men shadowing me." "Certainly," returned Cardona. "That was for your own protection." "But not at my request -" "I considered that unnecessary." Grell smiled. He was glancing at the desk top. Cardona was watching him. Neither saw the blackish streak that edged into the office, from the connecting door. Flat against the floor, that blotch formed a silhouette. Barely visible, it was the only indication of The Shadow's presence. Motionless, the silhouette became so inconspicuous that it could no longer have attracted attention. "RYTHE'S death was a shock," declared Grell, changing the subject in suave fashion. "I, too, wish to see that justice is gained; and I feel that you should appreciate my attitude, inspector. Police Commissioner Weston seems to understand my sentiments." "The commissioner?" snapped Joe. "When did you talk to him?" "This afternoon," replied Grell. "When I called him on the telephone, he apologized for last night's hasty remark. In fact, he invited me to accompany him this evening to see Professor Murkden." Cardona fumed inwardly. He realized that Grell, probably by flattery, had talked himself into the good graces of the police commissioner. Cardona regarded that as interference with his own activities. So he took it out on Grell. "I suppose," growled Cardona, "that you squawked about being covered by headquarters men. Going over my head, despite the fact that I sided with you last night -" "No," interrupted Grell, smoothly. "On the contrary, I spoke highly of you to the commissioner. I said nothing about being shadowed." Cardona was stumped. He saw how cleverly Grell had established himself. By speaking well of Joe, Grell had impressed Weston. Established with the commissioner, he was working the game in reverse. The humor of it finally brought a smile from Cardona. "All right," he acknowledged. "Go ahead and meet the commissioner to-night. I'll call off my men." "Thanks," smiled Grell. "Incidentally, I might add that I said nothing to the commissioner regarding the clue you found at Rythe's last night. I suppose that you chose to keep it to yourself." "The clue?" demanded Cardona, quickly. "What clue?" Grell leaned across the desk. "When I saw Rythe's body," he declared, in a confidential tone, "I was badly shaken, but I observed the slip of paper that had apparently dropped from his hand. It had writing on it, in blue pencil." Grell eyed Cardona as he spoke. Joe sat silent. "Large writing," added Grell. "I could read it easily. All it said was: 'Call me at noon to-morrow'; and it was signed with the letter 'L.'" Grell paused to note the effect of his statement. Cardona's silence was proof that Grell had a hit. The sallow man settled back behind his desk; his eyes became shrewd. "You were the next person who entered Rythe's den," reminded Grell. "Yet nothing more was said about that written memo. I fancied that perhaps you preferred to keep certain clues a secret. So I remained silent." Cardona saw no further use in blunt silence. He snapped a question: "Have you any idea who 'L' could be?" Grell shook his head. "I knew nothing of Rythe's affairs," he insisted. "Timothy might tell you." "I quizzed Timothy on my own," admitted Cardona. "He couldn't answer it. You struck it right, Grell. I found that piece of paper. But this case is mine. I've got a right to keep quiet about the clues I find. If the commissioner is to know about them, it's my business to tell him." Grell's eyes showed a sudden gleam; one that could be seen from the doorway where The Shadow watched. Grell had caught Cardona's reference to 'clues'; it indicated that Joe might have found something at Tabor's also. Cardona, however, was unconscious of the slip that he had made. Grell did not enlighten him. METHODICALLY, Cardona drew a small envelope from his inside pocket. Opening its loose flap, he peered within; drew out the blue-penciled memo that Grell had mentioned. Again, Grell's eyes were sharp. Cardona's action indicated that something else was in the envelope. "Here's the memo." Cardona showed it to Grell; then replaced it in the envelope. As he did, Cardona kept the envelope turned so that Grell could not see another item, the chess clipping that Joe had picked up at Tabor's. "All right, Grell. I'm glad we had this talk. You won't be bothered with anybody trailing you. In return, I'm counting on you to cooperate." Grell smiled. By cooperation, he knew that Cardona expected him to make no mention of this meeting, especially to Commissioner Weston. Grell nodded his agreement, arose with Cardona and helped the inspector put on his coat. The Shadow was gone when Cardona left by the outer office. Grell remained; but he was no longer watched by The Shadow. The reason for The Shadow's complete departure was explained when Cardona reached the lobby. There, Joe dismissed the detective whom he had told to keep tabs on Grell; then went out and took a cab. Hardly had Cardona's taxi pulled away before The Shadow appeared, carrying his brief case, to enter another cab. The Shadow had heard every word that passed between Cardona and Grell. He had recognized the importance of the blue-penciled memo that was signed with the letter 'L.' Whether or not Grell was positive that Cardona must have found a previous clue at Tabor's, The Shadow was certain that Joe had. Moreover, The Shadow was convinced that Cardona had gained a link between them. Cardona's prompt agreement to Grell's requests stood as proof that Joe had some important move in mind. The briskness of Cardona's departure fitted with it. Clearly, The Shadow could see the idea that was in Cardona's mind. The ace inspector did not fully trust Courtney Grell. Moreover, Cardona would not have kept important clues too long without telling Weston, unless those clues promised some quick result. Cardona's hurry was proof that he intended to follow a lead that he had gained; to accomplish some startling result between this hour - six o'clock - and the time when Grell met Weston. By trailing Cardona, The Shadow stood a chance to learn the link for himself. Events were fitting with The Shadow's theory that Cardona had become a vital factor in the plans of the supercrook who ruled the purple death. Trailing Cardona, The Shadow hoped to learn all that the inspector knew; to pick up further facts if Cardona failed to find them. This was a quest that promised results. Yet The Shadow, though prepared for unusual developments, did not consider his present trail as more than a preliminary one. The Shadow had not yet foreseen that circumstances might hold a real surprise in store, that his present mission was to bring him to the threshold of new mystery. CHAPTER VIII THE VANISHED SLEUTH FROM the moment that Cardona's trip began, it proved that some new development lay ahead. Joe's cab took a roundabout direction from Times Square. Obviously, Joe wanted to throw off trailers by picking side streets where he could watch for following cars. The Shadow, however, was equipped to match such a game. The cab in which he was riding was his own. It was an independent taxi driven by one of the cleverest hackies in New York; a driver whom The Shadow had chosen because of his skill. Instead of closing in on Cardona's taxi, The Shadow's cab kept well behind. At Sixth Avenue, Cardona's cab had made a quick turn southward, beneath the elevated pillars. The Shadow's cab turned also; trailed at a distance of nearly two blocks. Cross-traffic suddenly blocked the chase. It came just as The Shadow's cab was speeding to get by a cross street as all lights went red. Sleet and snow quickly blotted out Cardona's cab. Ten swiftly covered blocks failed to show new traces of the missing cab. Then, on one side street, The Shadow saw a parked cab that looked like Cardona's. The standing taxi had no lights. The Shadow ordered to keep ahead; then round the block. A few minutes later, his own cab entered the street with lights extinguished and stopped fifty feet behind Cardona's. The Shadow alighted and started forward through the hazy sleet that blurred the infrequent street lamps. He had gone but a few yards when he saw a figure step from a small alleyway near the cab ahead. Pausing by a doorway, The Shadow saw the outline of a gray hat and overcoat; he watched the wearer of the garments enter the taxi. The light was insufficient to distinguish more than a general impression of the gray-clad form; but The Shadow had recognized Cardona's garb. Obviously Joe had ordered a halt at this spot; then gone through the alley on foot. Cardona's cab shot suddenly away, as soon as its passenger had entered it. Its lights came on while it was moving. By the time The Shadow was back in his own cab, the tail-light ahead was disappearing around a corner. The Shadow ordered quick pursuit. THE new chase was a short one, performed in zigzag fashion. The first cab gained a long lead on a cross street where the avenues were wide apart. It turned right; by the time The Shadow's cab reached the avenue, there was no sign of Cardona's. The Shadow ordered a quick spurt on the avenue; a prompt turn to the right at the next street. He had gauged the situation to perfection. As his own cab turned right, The Shadow saw Cardona's taxi parked a short way down the block. Its lights were still on. It started from the curb just as The Shadow spied it. The trick was a cute one, if intended to shake off followers; for there was no way to tell whether or not Cardona had remained in the cab. It was possible that he paid the driver while on the move; stopped long enough to drop off and tell the driver to keep going. The Shadow, however, knew that he could depend upon Moe Shrevnitz, the driver who was handling his cab. With a quick command, The Shadow ordered Moe to slacken speed; then keep up the chase. Moe obliged. In the moment that the cab was almost halted, The Shadow opened the door and dropped off to the curb, easing the door shut as he went. Ten seconds later, The Shadow was at the very spot where Cardona's cab had stopped. Groping, The Shadow studied his surroundings. He soon found that he had picked the only spot where Cardona could have gone during the short time allotted him. The Shadow was in front of a little shoe repair shop. The tiny building was an old relic wedged between a loft building that had no side street entrance and a warehouse that displayed a blank wall. The shoemaker's shop was closed for the night. It was wide enough for a door and one display window that started from two feet above the sidewalk. Avoiding the blackened glass window, The Shadow tried the door. It was unlocked; hence it was possible that Cardona could have entered it quickly after leaving the cab. TWO possibilities occurred to The Shadow: one, that Cardona had arranged this trick to watch for pursuers; the other, that Joe had learned something about the shoe repair shop and had come to investigate it. In either case, the darkness was sufficient for The Shadow to attempt a silent entry. Soon after the chase had started, The Shadow had donned black garments from his brief case. Clad in that garb, he was as invisible as night itself, when favored by the presence of a darkened doorway. His mode of entry, edging in as he opened the door, cut off all draughts and whistling sounds of wind. One minute later, The Shadow was in the shoe shop, the door closed noiselessly behind him. The silence was so intense that The Shadow could have detected the slightest sound. Moving with absolute stealth, he assured himself that the little shop was empty. The Shadow used a flashlight, its tiny ray masked by a fold of his cloak. Foot by foot, he scoured the place. He found a row of shoe-shine chairs on one side; a shoemaker's lathe and machinery on the other. At the front, by the window, was a small desk with a telephone. The Shadow discovered this, probing without his light. At the rear of the narrow room was a door. It was bolted from the other side. It was possible that Cardona had gone through to the back of the building. The door could have been unlocked when Cardona found it. The Shadow's path was definitely blocked. Half a minute passed while The Shadow listened in darkness, to learn if any one could be listening from the other side of the door. He heard no sounds; but one suddenly came from the front of the shop. It was the ring of the telephone bell. Drawing away from the rear door, The Shadow waited a full two minutes. The bell kept up its persistent intermittent ringing all the while. Confident that no one could have detected his entry, The Shadow took it for granted that Cardona must have gone on through the rear of the shop, using the bolted door to cut off trailers. Joe was probably calling the number, to learn if any one had entered the shoe shop, hoping that such a person would answer. With a soft, whispered laugh, The Shadow moved forward. He lifted the receiver from the telephone hook; but did not speak. Instead, he listened. CARDONA'S voice came across the wire, as The Shadow had expected. But it lacked its gruff, demanding tone. The words that The Shadow heard were excited ones. "Whoever you are, listen!" came Cardona's quick tone. "This is Inspector Cardona, New York police. Get word to Commissioner Weston, at once. Tell him that I -" A click ended Cardona's outburst. Simultaneously, The Shadow sensed a puff of chill that penetrated the narrow shop. Dropping the receiver, he wheeled away from the telephone, whipped out an automatic and stabbed a shot to the rear door. Simultaneously with The Shadow's blast, revolvers barked in his direction Their shots were wide. Aiming men had picked the telephone as their target. Bullets shattered the glass show window. But The Shadow's shot told. He had picked the one spot from which an attack could come. He heard a cry; snarled oaths as crooks dragged back a companion whom The Shadow had wounded. Three quick shots roared through the shoe shop as The Shadow bombarded the opened door. Enemies had dived for cover, but The Shadow's bombardment served its purpose. Crooks could not close the door while it was under fire. If they took to flight, their scurry would tell The Shadow of their move. Then came the token that gave The Shadow knowledge of instant danger. As his automatic made its last recoil, he felt a barely perceptible quiver of the floor; heard a rumble from the front street. The Shadow was standing against the thin front door; to his left was the show window. With a quick dive, The Shadow flattened himself below the show window; between it and the telephone table. He was not an instant too soon. From the front street came a terrific rattle - the outburst from a battery of machine guns. The rumble had told The Shadow of an approaching truck. That vehicle had stopped. With downward tilted machine guns, crooks were riddling the whole front of the shoe shop. The door was splintered by a hundred drilling bullets. The broken window was shattered into nothingness, its glass fragments bouncing over and beyond The Shadow. The whole interior of the shop was ripped and peppered, except at one spot. That was the narrow, two-foot space where The Shadow lay prone; the only possible place where a person could have lain and lived. The Shadow was below the lowest possible angle of the machine guns. He was bulwarked behind a thick brick wall that the bullets could chip, but not demolish. The terrific bombardment ended. The truck roared away, its occupants satisfied that they had covered every square foot of the shoe shop with their bullets. The door at the rear of the shop slammed shut, its bolt clicked. The small crew behind the wall of the rear room were satisfied that The Shadow had been riddled. They had no time to investigate and gloat. They had to carry away a wounded member of their band before the police arrived. AS he arose, The Shadow stumbled over the telephone. The table had been riddled. The telephone had been hit, but it had fallen so quickly that its wires still remained intact. The receiver had been cracked by a bullet, but The Shadow could hear the dial tone. Calmly, he fingered the dial, found that it worked. Sirens wailed from an avenue. The terrific clatter had aroused the neighborhood. Still, The Shadow persisted with his call. A quiet voice answered; it was that of The Shadow's contact man: "Burbank speaking." "Report." "Report from Shrevnitz," responded Burbank. "He trailed Cardona's cab to the Cobalt Club. It is across the street -" Burbank's voice faded as the receiver crackled. The split had yielded; the wiring was useless. The Shadow dropped the telephone, turned to the front door. Sirens were closer. Soon they would reach the shoe shop. The Shadow stepped out into darkness, moved rapidly along the street. He was obscured by the sleety blackness by the time the first patrol car arrived. Elsewhere, The Shadow stepped aboard a cab that was parked near a corner, gave the driver a destination. Finishing a quick trip, The Shadow dropped a bill through the front window; stepped out and merged with darkness, leaving the driver wondering where his passenger had gone. A half block's walk brought The Shadow to a spot across the street from the Cobalt Club. The Shadow saw two cabs. Up ahead was Cardona's. Its parking lights were on; the driver was sitting patiently at the wheel. Behind was The Shadow's cab. Approaching, The Shadow stepped up from the darkness, gave Moe the whispered order: "Report." "Never lost sight of it," stated Moe, referring to Cardona's cab. Moe could not see The Shadow in the darkness beside the driver's window. "It came straight here, but nobody got out of it. What the hackie's waiting for, I can't guess." "Report received." Moe saw ghostlike blackness move beneath the glow of a street lamp; then fade as it reached the shelter of Cardona's cab. The Shadow had arrived there without the knowledge of Cardona's taxi driver. Noiselessly, The Shadow opened the rear door, peered into the back of the car. He could see the interior by light from the street side. As The Shadow had expected, the cab had no passenger, but it was not entirely empty. Carefully folded upon the back seat was Cardona's gray overcoat; on it was perched the old felt hat that Cardona had worn when he left Grell's office. Silently, The Shadow closed the door. He went back to his own cab, entered it and stowed away his black garments. Donning a hat and overcoat of his own, he spoke to Moe. The cabby started the taxi, drove around the block and pulled up in front of the Cobalt Club. There, The Shadow alighted in the guise of Lamont Cranston. A fixed smile was registered on The Shadow's disguised lips as he left hat and cloak at the club cloak room. Attired in faultless tuxedo, he strolled slowly toward the grillroom, where he knew he would find Commissioner Weston. The parked cab outside the Cobalt Club, the one in which Cardona had traveled, was a token which The Shadow knew would soon be explained. It had been sent here as a contemptuous challenge to the law. Some message from a master crook would surely come to give notice of its presence. The Shadow expected a prompt aftermath to the mysterious disappearance of Joe Cardona. CHAPTER IX CRIME'S SEQUEL COMMISSIONER WESTON was in the grillroom when The Shadow arrived there. Weston had come to dinner earlier this evening, for the grillroom clock showed that the time was only ten minutes after seven. Moreover, to-night, the commissioner had guests. With him were two newspapermen, special writers who conducted columns that covered society news. The press had found a way to gain interviews with Weston, even in the seclusion of the Cobalt Club. Ostensibly, these society writers had come merely to chat with the commissioner, disclaiming any interest in crime news. Actually, they were hoping for any wedge that might enable them to question Weston regarding the purple death. Weston knew that. He could not afford to be brusque with the society columnists. Nevertheless, he was wary. His interviewers had so far arrived nowhere. Weston smiled when he saw The Shadow. He knew that the columnists would be impressed when they learned that the commissioner was on close terms with Lamont Cranston. The globetrotter was much sought, socially; but seldom seen at society functions. Shaking hands with much gusto, Weston invited The Shadow to join the group for dinner. While they were waiting for The Shadow to finish his first course, Weston remarked that he had an appointment at eight o'clock. One of the newspapermen promptly questioned if the appointment happened to be Professor Murkden's lecture. Weston admitted that it was. "Some valuable facts may be mentioned to-night," declared the commissioner, tartly. "That is why I am attending the lecture." "And afterward?" persisted the newspaperman. "Will you discuss the blood tests that the professor has made?" "Probably," replied Weston. "The newspapers, however, have already received full reports of the tests that the professor made to-day." That closed the subject. Weston felt that he was sitting easily, until he saw a man walk hurriedly into the grillroom. The arrival was Courtney Grell. The sallow man's anxious expression told that he was looking for the commissioner. Before Weston could signal Grell to stay away, he arrived at the table. One of the newspapermen recognized him, for Grell had formerly tried to splurge in society. Weston was therefore forced to admit Grell's identity. "What is it, Grell?" he demanded angrily. "I told you to meet me at Professor Murkden's at eight o'clock. I did not say to come here." "But I was told to come here -" "By whom?" "By your secretary. He called up my hotel and -" "My secretary has gone away on vacation." "That is singular, commissioner. The man who called wanted me to tell you that the taxicab was still waiting outside the Cobalt Club." WESTON arose, fuming. "What nonsense is this, Grell?" he fairly shouted. "Why should I keep a cab waiting? I have my official car." "But the cab is there, commissioner. I spoke to the driver. He said that he was waiting for word from you." "Who told him to wait there?" "He said that Inspector Cardona sent him here." Weston glared, more perplexed than ever. At that moment, an attendant entered the grillroom, to announce that there was an urgent telephone call for Commissioner Weston. As soon as Weston left the grillroom the newspapermen arose and followed. The Shadow saw Grell watch the departure with shrewd gaze; then the sallow man followed. The Shadow had just finished his course. He arose and strolled after the throng. Weston was in the lobby, shouting over a telephone, oblivious to all about him. "Yes... This is Commissioner Weston!... Hello... Cardona?... What?... Where?..." The receiver went dead in Weston's hand. Hanging up, Weston started to say something; then stopped and turned to Grell, whom he saw standing by. "Send some one for that taxi driver," snapped Weston. "Bring him here at once." Grell dispatched a pair of attendants. They returned, with a worried-faced cab driver. One of the attendants was bringing a gray hat and overcoat. He gave them to Weston, with the remark: "These were in the back seat, sir." "Cardona's hat and coat!" exclaimed Weston. "Then it was Cardona who just called me. Something has happened to him. Come, my man" - this was to the taxi driver - "give me your story." "I don't know nothing much," blurted the hackie. "I was cruising near Times Square, along about six o'clock, when a passenger got aboard and told me to drive for Sixth Avenue." The Shadow was watching Grell. He saw the man indulge in a tight-lipped smile, when the cabby failed to mention that Cardona had boarded his cab outside the Landis Building. "When we got to Sixth Avenue," continued the hackie, "this fare of mine tells me to go back to downtown. I thought maybe he was kidding, until he flashes a badge; says he's Inspector Cardona. Downtown, he tells me to swing on Twenty-eighth Street and park near a sort of alley, with the lights out." THERE was an interruption; another call for Weston. This time, the caller was not Cardona. Weston held brief conversation; announced that he had received a routine report from headquarters. He told the cabby to proceed. "The inspector was gone a while," continued the hackie. "He showed up again, talked gruffer than he did before. Told me to turn one corner after another; then he stopped me all of a sudden in front of a joint that looked like it didn't amount to much. He shoved me five bucks, told me to chase up here and wait until I heard from the commissioner." "What about the hat and coat?" demanded Weston. "When did Cardona leave them?" "I don't know," admitted the hackie. "I didn't know they was laying in the cab until we just found them, a couple of minutes ago." Weston looked quizzical. Suddenly a thought struck him. "The second place you stopped," he inquired, "was it a shoe repair shop? Between a loft building and a warehouse?" The cabby nodded. "Yeah," he said. "That could have been it. On Twenty-fourth Street, I think." Weston turned to the others. The commissioner's face was strained. "This man has told the truth," announced Weston. "It fits with the report that I just received from headquarters. Cardona must have entered that shoe shop. Not long afterward, a truck stopped there and riddled the place with machine gun bullets. The assassins escaped." "After killing Cardona?" The question came from one of the newspapermen. Weston was too worried to realize who had asked it. "No," declared Weston. "Fortunately, Cardona is still alive. I know that, because I heard his voice across the telephone, only a few minutes ago. But he has certainly been captured. He had something that he wanted to tell me; he said that this might be his last chance." "Another investigator missing," said one newspaperman to the other. "This time, it's Joe Cardona, best inspector on the force. He tried to tackle the purple death. He's gone. The best he could do was put in a last call -" Weston was roused to sudden ire. He began to denounce the men who had so recently been his guests. While Weston was storming, the columnists made a scramble for the cloak room, obtained their coats and hats and headed for the street. "They'll call their offices!" fumed Weston. "There will be special editions on the street inside an hour. What can be done about it, Cranston?" "Notify the other newspapers," suggested The Shadow, calmly. "Give them the whole story, so that those two chaps won't have a scoop. Then come to the grillroom and finish dinner." Weston managed a chuckle. "That's taking it calmly, Cranston," he decided. "I shall do as you suggest. In addition, however, I shall notify headquarters that Cardona is missing. We must begin an intensive search for him." SOON afterward, Weston joined The Shadow and Grell at the dinner table. Weston had made his calls; he had calmed considerably and announced that he intended to go to Murkden's lecture at eight. "Professor Murkden may be our last resort," affirmed Weston, gloomily. "He is not an investigator, but his scientific tests have given the only tangible results to date." The Shadow noted Grell, who was poker-faced. He knew that Grell was thinking about Cardona's clues. The Shadow, too, was considering that subject. He was positive that Cardona had picked up some small item at Tabor's, the night before he found the memo at Rythe's. In addition, however, The Shadow was considering Cardona's disappearance. He had solved certain details of that riddle. The Shadow, from his own experience, knew that Cardona could not have entered the shoe repair shop. That was a trap that crooks had arranged for any one who might be following Cardona, particularly The Shadow, himself. It proved that the purple killer had acquired another band of gunners, like the crew that Slook Howdrey had commanded. The Shadow knew that Cardona had definitely left the cab at the first stop it made - on Twenty-eighth Street. Joe had been gone for twenty minutes before The Shadow located the parked taxi. It was during that period that the ace inspector had been seized. Cardona had been captured not far from the cab. Another man - one of the captors - had donned Joe's coat and hat. That substitute was the man whom The Shadow had seen returning to the cab. Crooks had picked a man of Cardona's stocky build for the assignment. Viewing the fellow in darkness, The Shadow had seen only the outline of the gray coat and hat. In the cab, the substitute had told the hackie to drive to the shoe repair shop; then continue to the Cobalt Club. The substitute had left Cardona's hat and coat. He had ducked into the shoe shop, gone through the back door and bolted it. There he had joined other waiting thugs. Meanwhile, crooks had imprisoned Cardona. They had dialed the number of the shoe repair shop, had given Cardona a chance to get hold of an extension telephone, while thinking he was unobserved. Cardona had taken a chance on reaching the commissioner through the person at the other end. A clever trick to surprise The Shadow if he happened to be in the shop. Crooks in the rear room had been ready to fire when they heard the ringing cease. Another had signaled the machine gun truck, from the back door of the old shop. The call to Grell could have come from any one claiming to be Weston's secretary. As for Cardona's call to Weston, that was simply explained. Crooks had let Cardona get to a telephone on his own; had kept watch and broken in upon him before he could tell too much. This time, the work of henchmen showed that they were under direct orders from the purple killer. Only a master crook could have devised such a crafty sequence. Only the purple killer would have been so bold as to fling deliberate, disdainful challenges at the police commissioner. Cardona's capture was plain to The Shadow; yet he still needed facts before he could learn where crooks held their prisoners. To gain such facts, The Shadow intended to follow his accepted course. Blind search would prove of no avail against a superplotter. Only by uncovering the purple killer, by learning the master crook's identity and methods, without the fiend's own knowledge, could The Shadow plan the rescue of Joe Cardona and bring a final finish to the run of crime. CHAPTER X THE NEEDED LINK WHEN eight o'clock neared, Weston departed for Professor Murkden's accompanied by Courtney Grell. The Shadow remained at the Cobalt Club, stating that he had an appointment. He remarked, however, that he might be able to visit Murkden's after the lecture. That pleased Weston. In this time of stress, the commissioner appreciated the presence of his friend Cranston. For some reason that Weston could not explain, he felt more confident when Cranston was about. Soon after the commissioner had gone, The Shadow left the club. Moe's cab wheeled over, picked up the supposed Lamont Cranston. The Shadow gave a destination; the address was close to Murkden's. As the cab headed in that direction, The Shadow donned his garb of black. To The Shadow, the disappearance of Joe Cardona marked a crisis in the sequence of purple death. Until this time, The Shadow had been forced to play a waiting game, even though other lives - those of unknown persons - might be at stake. All along, The Shadow had recognized some blockading factor; to-night, he had discovered what it was. Joe Cardona, by holding out important clues, had unwittingly restrained The Shadow. Cardona's disappearance was doubly unfortunate; for The Shadow was convinced that Joe had gained two clues. Something that Cardona had found at Tabor's must have linked with the penciled notation at Rythe's. In some way, Cardona had managed to gain a definite lead, and had gone after it too soon. For the present, The Shadow's policy could not be altered simply because Cardona had blundered and made himself a prisoner. If Joe should be slated for death by his captors, the chances were that he had already been put on the spot. If they intended to hold Cardona as a hostage, there would be no need to attempt a hasty rescue. The Shadow saw that it would be wiser to wait until his plans were fully formed; unless some emergency made it imperative to take great risks in Cardona's behalf. Cardona's disappearance had, in a sense, helped The Shadow. It had given him two definite leads of his own. The first concerned Courtney Grell. To-day, The Shadow had learned definitely that Grell was playing a cagey game. That did not necessarily implicate Grell in the crime chain of the purple death. Grell's discovery of Rythe's body could have been an accidental one, as Grell himself claimed. Nevertheless, Grell had smartly looked out for certain interests of his own. He had played Cardona against Weston; then vice versa, in order to put himself in right with the law. That, of course, was understandable. His smartest trick had come when he mentioned the memo clue to Cardona. At that time, Grell had learned - if he had not guessed it before - that Cardona held a clue from Tabor's as well as from Rythe's. Grell had not even suggested to Cardona that he suspected there was a first clue. As for the second one, Grell had promised not to mention it to Weston. True, he had kept that promise, but under unusual circumstances. When he heard that Cardona had vanished, Grell should have told everything to Weston, so as to aid in the search for Cardona. Grell's silence proved that one of two situations existed. Either Grell saw how he could gain some personal advantage through Cardona's disappearance, or else he was in some way connected with the purple deaths. In either case, Grell would be due to make a move. The Shadow intended to watch Grell. HE had postponed such a vigil partly because Grell would be with Weston until nine o'clock, when Professor Murkden's lecture ended. Grell could make no move until after he left the commissioner. For the present, therefore, The Shadow was actually using Weston to hold Grell inactive. Also, The Shadow needed the hour between eight and nine; at least a portion of it. He wanted to follow the second lead that he had gained through Cardona's disappearance. Joe Cardona had established the deaths of Tabor and Rythe at identical times on successive nights; namely, at eight-thirty. In making blood tests, Professor Murkden had proved Cardona's findings. Yet Cardona had not been seized because he had settled the time element, nor had any threat been made against Murkden after the results of the professor's tests had been published. That was singular; because the greatest subtlety of the poison used in the purple murders lay in the way of baffled physicians when they tried to ascertain the hour of each death. Therefore, The Shadow had considered the possibility that both Cardona and Murkden might be wrong in their conclusions. Cardona had relied upon guesswork; and The Shadow had already doubted Joe's hunches. Murkden, however, had made exact tests, scientifically conducted and properly attested by competent observers. In his tests, though, Murkden had relied upon a synthetic formula that he called Compound "F." There was a chance that the chemist had erred slightly in his preparation of the compound; that it was not exactly identical with the purple poison used by some master murderer. To settle that, The Shadow had resolved to make tests of his own. The coming hour offered the best opportunity for The Shadow to obtain the materials that he needed. It was ten minutes after eight when The Shadow's cab stopped at a spot not far from Murkden's. Stepping into darkness, The Shadow merged with the sleety night. Snow was increasing; large flakes settled on the shoulders of The Shadow's cloak, but they vanished before they could serve as white markers to indicate the passage of a form amid the darkness. Nearing Murkden's, The Shadow saw Weston's car out front; near it, a pair of uniformed policemen. The officers were not regular watchers. Guards had been deemed unnecessary because Murkden's house was strong and he had three competent servants. The pair of bluecoats had been stationed to protect Weston's chauffeur, in case another ruffian like Slook Howdrey tried to take over the commissioner's official limousine. GLIDING into a side passage just short of Murkden's house, The Shadow escaped the notice of the officers. He reached the windows of Murkden's basement laboratory. There, with a small screw driver and a compact jimmy, The Shadow began the task of entry. The job was speeded because The Shadow had previously studied the inside fastenings, when he had visited Murkden's. At the finish of five silent working minutes, The Shadow had removed the outer bars. Noiselessly, he pried the inner sash. Raising the window slightly, he slipped into the laboratory. A corner light was illuminated, but the room was empty. After closing the window, The Shadow operated rapidly. He found a box of new test tubes; from dozens the few that he took would not be noticed. Into these, he poured samples of the various compounds that were on Murkden's shelf. New corks were plentiful in a special box. The Shadow corked the tubes, carefully packed them in a pocket beneath his cloak. Searching among a stack of notebooks, The Shadow found one that he wanted. It contained neatly typed pages, covering the results of Murkden's blood tests. Rapidly The Shadow chose the notations that he knew would be necessary for his own experiments. He copied these, thus gaining needed formulas and complete data concerning the blood changes that had occurred both with human victims and guinea pigs. That done, The Shadow examined some of the slides that Murkden used with the projector; noted their labels and made brief written descriptions concerning certain slides. He passed the corner where a small box of dead guinea pigs lay upon the crate that was filled with live ones. The Shadow ignored the cavies since there was no need to carry away live guinea pigs. As for the dead ones, their purpose had been served. All that was important concerning them could be found in The Shadow's notes. It was not quite quarter of nine, The Shadow decided to look in upon the lecture before he departed. Choosing a set of thin pass-keys, he unlocked the door to the stairs. He ascended and opened the next barrier as easily. At the third door, The Shadow paused; probed the lock with consummate care. This was the door to the lecture room. The Shadow handled it without noise. Inching the door open, The Shadow viewed the lecture room through a narrow crack. He could not see the platform where Murkden stood, for that was against the wall beside The Shadow's door. He could hear the professor's dry voice, however; and he caught the thuddy sounds that came when Murkden tapped a big chart with a pointer. Murkden's listeners were visible. They formed an attentive group of note-takers who were looking toward the platform. Near the back of the room, The Shadow saw two who were not taking notes. One was Commissioner Weston. Arms folded, face set, Weston was methodically taking in everything that Murkden said. The other was Courtney Grell. His attitude was a contrast to Weston's. GRELL looked bored and restless. He was slouched in a chair. His jaw was moving as he chewed gum to pass the time. Even that annoyed him. The Shadow saw Grell take out his wad of gum and throw it into a wastebasket a few feet away. Sourly, Grell reached in his pocket and produced a cigar. He chewed the end from it and brought out a pocket lighter, to ignite the stogy. Murkden's drone now ceased. The Shadow heard the rap of the pointer upon a table. "Attention, please!" came Murkden's sharp voice. "We can tolerate no smoking during the lecture." Students stirred to look toward Grell, for Murkden's gaze must have been directed on the visitor. Grell quickly thrust the cigar in his breast pocket. He looked apologetic when Weston gave him a reproving gaze. Grell straightened in his chair. Murkden resumed. Immediately, Grell slouched again. Since he could not smoke, he brought out a package of chewing gum and took a fresh stick. Again, his eyes roamed restlessly; they stopped suddenly on a table that was near the wastebasket. The Shadow saw a shrewd look on Grell's face. Noting that Weston was not watching him, the sallow-faced visitor edged toward the table and reached for a newspaper that was lying there. Bringing the newspaper to his chair, Grell stooped and began to turn the pages. The newspaper crinkled slightly, but none of the listeners noted it. Only Professor Murkden could have seen what Grell was doing, but this time the professor was apparently too busy with his lecture to again note the disturber. The Shadow saw Grell raise the newspaper; then turn it over. On the side toward The Shadow was a large automobile advertisement. It was the same page that Grell had seen on the newspaper that Cardona had brought to the office. Grell had remembered that newspaper the moment that he saw its duplicate here in the room. The Shadow recognized the large advertisement as one that he had seen; thereby, he identified the particular morning newspaper which Grell held. But The Shadow had not seen Cardona's newspaper. When he had visited Grell's offices, Joe had stowed that copy in his overcoat pocket just prior to The Shadow's entry. Grell's interest in the newspaper, however, impressed The Shadow as important. The result proved it. Grell's eyes lighted as he found an item. A look of sudden elation swept the swindler's sallow countenance. Folding the newspaper, Grell reached over and replaced it on the table. Looking to the left, Grell saw the door that led out to the little reception room that formed an entrance to the small lecture hall. His jaws slowed their chewing motion as he turned his gaze toward the platform; then glanced at Weston. The Shadow understood the move that Grell intended. As soon as a convenient opportunity offered, Grell intended to leave. He wanted to get away before the lecture finished. He planned to depart without attracting Commissioner Weston's attention. Grell's reason for departure concerned something that he had noted in the morning newspaper. THE SHADOW edged the door shut, locked it noiselessly. He made a quick descent to the laboratory, rapidly locking the other doors as he passed them. Out through the window, he closed the sash, planted the crisscrossed bar that he had removed. A single minute was all that The Shadow required to jam that outer fastening. Gliding through darkness, The Shadow regained Moe's cab. Stowing his black garb in his brief case, he ordered the driver to head for the corner nearest to Murkden's. As they reached the corner, The Shadow saw some one coming down the steps of the professor's house. He knew that it must be Grell. The Shadow dropped off. The cab arrived in front of Murkden's and Grell hailed it. The Shadow saw him step aboard. The cops outside offered no objection. They were not under instructions to stop persons who came from Professor Murkden's lecture. The Shadow had given Moe brief instructions. Watching the departing cab, he saw its stop-light give two slow blinks, as Moe pressed the foot-brake. Then came four short ones. The two meant twenty; the four stood for four. That told The Shadow the number of blocks. All that he needed was the direction. The cab turned southward at the corner. This was Sixty-sixth Street. The Shadow knew that Grell had told Moe to take him to Forty-second. Probably to Times Square, where Grell would change cabs. That did not matter; Moe would manage to trail him. Grell would not walk far, looking for another cab amid the driving sleet. On foot, The Shadow made for the nearest subway. Reaching a local station, he had time to stop at the news stand before the train arrived. The Shadow asked for a copy of the Morning Sphere, the journal that he had seen Grell consult. The dealer had a few odd copies beneath the counter. Riding southward in a half-empty subway train, The Shadow opened the newspaper in the calm, indifferent fashion that suited his guise of Lamont Cranston. He found the page with the automobile advertisement. He scanned the page opposite it. Chess diagrams showed near the bottom of the page. They belonged to a half column of chess problems. Below were answers to problems printed on the previous day. In addition, The Shadow saw an extra diagram. There was a notation stating that this was a problem that had appeared one week ago. It was reprinted because a reader of the column had submitted a better answer, wherein White could produce checkmate in two moves instead of three. With the diagram was a terse letter of half a dozen lines from the reader who had presented the new solution. It was signed by a man named Louis Lenger. It gave Lenger's address, a number on Twenty-sixth Street. THE subway train was nearing Forty-second Street. The Shadow did not rise. He intended to keep on the local until he arrived at the Twenty-eighth Street station. Thin lips showed the semblance of a smile that meant an important discovery by The Shadow. The Shadow had guessed the nature of the clue that Cardona had found at Tabor's studio. It was a copy of the original chess problem, clipped from a week-old newspaper. In Rythe's den, The Shadow knew, Cardona had picked up a penciled memo signed with the letter "L." Cardona had been noting the chess column in the Morning Sphere in hope of some lead that would help him. To-day, he had seen this reprint of the problem; he had read the letter signed by Louis Lenger. Those initials looked like a sure hit. Either "L" - Louis or Lenger - would fit the initialed memo! That was why Cardona had halted his cab on Twenty-eighth Street. It was close enough - yet not too close - to Lenger's address. Cardona had evidently intended to return to the cab; instead, he had been captured during his round trip. The Shadow remembered a newspaper that had bulked from Cardona's overcoat pocket, when the inspector had left Grell's offices; but The Shadow had not seen the newspaper closely nor had he regarded it as important. He recalled that there was no newspaper in Cardona's overcoat when it arrived in the empty cab; but had logically supposed that Cardona had simply disposed of it. Courtney Grell must have noted the paper in the office and observed that Cardona valued it. That was why Grell had gone after the duplicate copy among the newspapers on the table at the lecture room. Grell must also have noticed the page at which Cardona's journal had been opened. Spying the letter signed by Louis Lenger, Grell had naturally hit upon the connection between that name and the letter "L." Grell, too, knew that Cardona had been near Twenty-sixth Street. For some reason, Grell had taken upon himself the dangerous job of visiting Louis Lenger. The Shadow knew that he would find Grell at Lenger's. He would be present when the two men met. To The Shadow, that coming meeting would offer facts that might aid him in solving the riddle of the purple death. CHAPTER XI THE LAST NAME THE address on Twenty-sixth Street was of a small apartment house; a building that looked new when compared to the old houses near it. The Shadow came along the street on the side where the apartment house was located. He passed the small entry where a light shone through a glass door. Again, The Shadow was obscured by darkness. He had brought his brief case with him. After leaving the subway, he had put on his blackened garments. On this secluded section of Twenty-sixth Street, lights were feeble, encrusted with freezing sleet. The terrain was well suited to The Shadow's mode of unseen motion. The Shadow avoided the front of the apartment building; not only because there the light was stronger, but because he expected the arrival of Courtney Grell. The Shadow knew that the sallow-faced schemer could not have arrived as quickly by cab as The Shadow had by subway. With time to spare, The Shadow crossed the street. From a darkened spot, he viewed the little apartment house. An angled outlook gave The Shadow a good idea of the building's construction. The apartment house was nothing more than a pair of converted residences that had been joined and equipped with a false front. From straight across the street, the structure presented a good appearance; its modern style indicated that the added construction had been done within the past few years. From an angle, however, the roofs of the old houses showed at the sides and gave an ugly contrast. The chief reason why they were visible was because they extended deep into the building block. Furthermore, there were spaces on each side of the apartment house. Those indicated routes to the back of the double building. The Shadow conjectured that there must be a regular rear entrance. The apartment house was four stories high. There were dim lights in windows on the first three floors, but none on the fourth. The top-story apartments were either vacant, or the occupants were out. Soon after The Shadow had completed his survey of the building, a taxicab pulled up and a man alighted. It was Courtney Grell. The Shadow watched the sallow man pay the driver. The cab went away. Grell entered the apartment house. Immediately, The Shadow crossed the street. He drew close to the doorway, stopped on the very fringe of the lighted space in front. Grell was standing in the entry thumbing a button on the wall. He had evidently found Lenger's name card. There was no answer to Grell's ring. The sallow man brought out a watch. He eyed the time, turning the dial toward the light that topped the entry. The Shadow saw the face of the timepiece, noted that it was quarter past nine. Grell gave a few more futile jabs at the button, shrugged his shoulders and turned toward the door. The Shadow drew back in darkness farther than necessary to avoid Grell's observation. The reason for his extended move was a taxicab, slowing as it came along the street. Like Grell's cab, this taxi stopped in front of the apartment house. GRELL had paused in the lighted doorway. Sharp-eyed, he was studying a man who stepped from the cab. The newcomer turned into the light. He was tall and heavy of build; his face, though rugged, seemed that of a thinker rather than a man of action. The tall man was almost shabby in attire; his heavy coat was opened, his derby hat was tilted from a jolt that it had received in the cab. The tilted hat displayed a shock of gray hair that showed no signs of recent brushing. The tall man's face was unshaven, another indication that he cared nothing about his personal appearance. He was not bothered by the tilt of his hat. He left the derby canted. Deep in thought, he stepped toward the door of the apartment house, his ungloved fingers fumbling the change that he had received from the taxi driver. Almost at the door, the tall arrival saw Grell and pulled up with a start. For the moment, The Shadow saw large eyes glare and study the sallow man with suspicion. Grell smiled; then queried affably: "Are you Mr. Louis Lenger?" Eyes hardened; then the tall man nodded. Grell held out his hand. "My name is Courtney Grell," he explained. "I happened to be in the neighborhood; stopped by to see if you were busy. I hoped that you would not mind the intrusion. I am a chess player like yourself." Lenger stroked his stubbly chin. He seemed torn between two sentiments: a natural dislike of strangers, and a feeling of friendliness toward a fellow chess enthusiast. At last he motioned toward the doorway and extended the gruff invitation: "Come up to the apartment, Mr. Grell." Grell let Lenger go past to unlock the inner door of the entry. He was still chewing gum; his slow-moving lips formed a suave smile. Then his eyebrows arched as he saw Lenger open the door without unlocking it. Evidently any one could gain access to this apartment house. The reason for the unlocked inner door was apparent to The Shadow when he approached. Though he did not enter, The Shadow made a careful study of the entry that the two men had vacated. He saw that the telephone receiver, used for conversation between visitors and tenants, was one that had no wire. On that account, the front door was open. People could go up and knock at the doors that they wanted. The uselessness of the receiver indicated that the bells, too, were out of order. On the other side of the entry, above a row of mail boxes, The Shadow observed a square-cut block that indicated a space for a new telephone installation. Evidently new equipment had been planned but not completed. Instead of going in by the front, The Shadow moved through darkness, skirted the double building and came to the expected rear entrance. He found a locked door, but opened it with little difficulty. He entered a long, dimly-lighted hallway. There, The Shadow saw the door of an automatic elevator. Its glass panel was dark. Lenger and Grell had evidently taken the elevator upstairs. THE SHADOW found a darkened stairway, ascended it. He stopped at the second floor and noted the frosted glass panel in the metal door of the elevator shaft. He found it dark. Keeping on to the third floor, he found another darkened panel. On the fourth floor, The Shadow saw the glow of the elevator through a door panel. He knew that Lenger's apartment must be on this floor. The fourth floor was smaller than those below; it had only two apartments and neither bore a name card. Light showed beneath the crack of one door. The Shadow knew that it must be Lenger's. Looking for a suitable way of entry, he went along the hall. Past an arch that had been cut in an old house wall, The Shadow saw doorways on each side of a short hallway. These had no numbers. They looked like service entrances to the two apartments. Working the door on Lenger's side of the house, The Shadow silently unlocked it. He stepped into a dusty kitchen, where pots, pans and dishes were stacked in untidy heaps. The kitchen was partly lighted by a glow that came from a hall. Thanks to that illumination, The Shadow avoided a blocking soap box that was stacked with opened tin cans. The Shadow crossed the hallway, peered into a fair-sized living room. He saw Lenger seated in front of a small table, busy with a board and chessmen, while Grell looked on; The Shadow had expected this. He knew that Grell would have talked about the chess problem, to follow up his method of introducing himself to Lenger. "Very good," commended Grell, as Lenger looked up from the board and pointed to his final move. "Your method of mate is far superior to the one originally published. I wish that I had more time to devote to chess problems." As he finished speaking, Grell removed his chewing gum and looked about for a wastebasket. He finally found one; tossed the gum there. A wastebasket looked out of place in Lenger's living room, for the place was strewn with papers and other rubbish. Lenger observed Grell's survey of the room and smiled apologetically. "The apartment is untidy," he admitted. "Unfortunately, my servant was offered a better situation and took it. I have not yet replaced him." "I see," nodded Grell. Then, suavely: "You live entirely alone?" "Yes. My investments bring me a small income. I cook my own breakfast and lunch, read, and do chess problems most of the day. I always dine at six; after that, I call on my friend Howard Feasley." "A chess player?" "Yes. Feasley is a recluse like myself. For a while, he was an invalid; but his health has improved. He still insists on retiring at nine. That is why I always go to Feasley's to play chess. Every night we play from seven until nine." Lenger was becoming quite confidential with Grell. The ice once broken, he seemed talkative. He did not, however, state where his friend Feasley lived, although Grell's face showed that the visitor would have liked to learn that fact. Instead, Lenger went to a bookcase, rummaged among stacks of volumes and found a tin box. He brought it to the table, where Grell was starting to chew another stick of gum. "I have worked on all these problems," remarked Lenger, opening the box to show a pile of clippings. "Whenever I work out a better solution than one in the newspaper, I write a letter to the chess editor." AS Lenger tilted the box to rearrange the clippings, something clicked and rolled to the table. The Shadow saw Lenger pick up a blue pencil and replace it with the clippings. So did Grell. The sallow man pursed his lips, glanced at his watch. "Nine-thirty," he remarked. "I must be going, Mr. Lenger. By the way, do you retire early, like your friend Feasley?" "Seldom," replied Lenger. "Why?" "I thought that I might drop by some evening," returned Grell, "and play a few games, after you have returned from Feasley's." "Fine!" agreed Lenger. "We could play from nine until midnight." "How would to-morrow evening be?" "Excellent. Can you come at nine, Mr. Grell?" "I am not certain. But jot down your telephone number" - Grell motioned toward a pad that lay on the table - "I can keep it as a sure reminder to call you -" "I have no telephone here." Grell's eyes narrowed. The Shadow knew why. Grell had failed in his effort to gain a specimen of Lenger's handwriting. He dropped that endeavor rather than arouse Lenger's suspicion. "I shall drop by again," promised Grell. "If I can not stop off, I shall leave a note in your mail box. Good night, Mr. Lenger." Grell picked up his hat and coat. Lenger reached for his own frayed overcoat and derby. "I'll accompany you downstairs," suggested Lenger. "I forgot to make some purchases at a drug store. We can chat about chess as we go along." The two left by the main door of the apartment. The Shadow listened until he heard the dull rumble of the descending elevator. Then he entered the living room; there, he went to the bookcase and examined the tin box that Lenger had replaced. Thumbing quickly through the stack of chess clippings, The Shadow found that many of them were duplicates. There was one copy of the original problem that Lenger had answered in to-day's newspaper; but no duplicate. Newspapers were stacked everywhere on the floor. They showed gaps where Lenger had clipped chess problems. Many of the journals were from out of town. Whether or not Lenger had other interests - murder, perhaps, included - it was certain that he was a true devotee of chess. Most of the books on the narrow shelves were volumes that referred to chess. The bottom shelves were stacked with dusty magazines; beneath them were boxes of various sizes. As a result, the old magazines formed a wavelike line. Carefully, The Shadow withdrew some of the boxes, so that he could examine them without disturbing the arrangement. Some of the boxes contained chessmen; others held articles clipped from magazines, referring to chess. A few were filled with miscellaneous items. It was in one of these that The Shadow made an important find. He saw a page that had been cut from a college catalog. It bore names of faculty members. Around one was a circle, marked in blue pencil. THE name was that of James Ardess, the university instructor who had been one of the earlier victims of the purple death. Beneath the torn page was a pawnbroker's ticket. It carried the name of William Gringew. He was the pawnbroker who had been another of the mysterious victims. Farther down, The Shadow found a business card, of neatly engraved pattern. It was old and dusty; the card bore the name of Frederick Tabor, with the title: "Architect." Next, The Shadow discovered a small-typed page, roughly torn from a copy of "Who's Who." Names on that page began with "R." Among them, circled in blue pencil, was a brief biography of Trumbull Rythe, the financier who, like Tabor, had been a victim of the purple death. At the very bottom of the box, The Shadow unearthed a folded sheet of paper. It bore a list of typewritten names, in capital letters, badly off line. This list carried the names of the victims of the purple death, in the order of their doom. Ardess and Gringew were early in the list. Later came Frederick Tabor; then Trumbull Rythe. There was an old typewriter near the bookcase; probably the list had been typed on that machine. The Shadow did not wait to check that matter. Something more important concerned him. The name of Trumbull Rythe was not the last one on the list. There was another below it. The final name was Horace Selbart. A name that had been in the news to-day. Horace Selbart, big time gambler; controller of gaming interests throughout the United States, had arrived in New York this afternoon, aboard a liner from Europe. He had been photographed by cameramen, on the roof of his penthouse near Park Avenue. Thus The Shadow knew who Selbart was, and where the man could be located. Both facts were vital. Selbart's unsavory past could be disregarded. All that mattered was that Horace Selbart had been slated as a victim of the purple death. Apparently, doom's chain had been timed to fit Selbart's return to America. Quickly, The Shadow replaced the box beneath the magazines. He left by the front door of the apartment. The elevator was on the ground floor; The Shadow did not waste time in pressing the control button and waiting for the slow car to ascend. Instead, he took the stairs. Reaching the ground floor, he hurried out through the rear door. The lack of a telephone in Lenger's apartment made The Shadow's spurt imperative. An instant warning must be dispatched to Horace Selbart. Yet with all his speed, The Shadow knew that his present cause would probably be useless. It was almost ten o'clock, the approximate time at which the last two victims of the purple death - Tabor and Rythe - had been discovered dead. Unless some unusual factor had delayed the purple murderer, The Shadow would be too late to save Horace Selbart from his scheduled doom. CHAPTER XII DOOM'S LONE CLUE FIVE minutes distant from Lenger's apartment house, The Shadow reached a telephone, located in the gloom of a side entrance to an antiquated office building that stayed open for the benefit of late tenants. The Shadow made a quick call to Burbank, for he knew that Selbart's number would be unlisted. Burbank, however, had an excellent collection of unlisted numbers, always in readiness. The Shadow knew that Selbart's would be among them. Burbank's response was prompt. To the contact man The Shadow delegated the duty of calling Selbart and delivering a warning. Burbank was excellent at that sort of job. His even, methodical tones carried an impressive touch across a telephone wire. The call finished, The Shadow returned to the street. He saw a chance cab parked near the corner; its fidgety driver was ready to pull away as soon as a traffic light turned green. Evidently the hackie figured that he would make out better cruising on this stormy night than by standing still. The hackie was wrong. As he shoved the car in gear, he heard a quiet voice speak from the back seat. Turning about, he stared into darkened depths. The voice gave a destination near Park Avenue, told the hackie to hurry. The fellow gawked no longer. He had the passenger he wanted. The fact that his fare had seemingly come from nowhere was a secondary matter. As he drove along, however, the cab driver was determined to keep tabs on his passenger. He did not want to let that unseen rider slip away as weirdly as he had arrived. None the less, the hackie's vigilance failed him. One block from the given destination, the cab slowed to make a final right turn. Something fluttered from the driver's shoulder; when it reached his lap, the man saw that the object was a five-dollar bill. Jamming the brakes, the hackie looked into the back seat. He turned on the dome light. The mysterious passenger was gone. The Shadow had seen another cab coming from a side street. It was the one manned by Moe. Burbank had evidently contacted The Shadow's speedy cab driver after calling Selbart's penthouse. The Shadow boarded his own cab as it slackened on the crossing. Once inside, he whispered the word: "Report." MOE gave the news. Burbank had called Selbart but there had been no answer from the gambler's penthouse. Burbank had dispatched Moe to be in readiness, should The Shadow need him. The cab neared the apartment house where Selbart lived. Dropping off, The Shadow noted the front entrance of the building. It was an old structure, only ten stories high; but its nearness to Park Avenue had kept it fashionable. The Shadow saw a uniformed doorman pacing the lobby. Ordinarily, the attendant belonged outside; but he had gone indoors because of the miserable weather. Looking upward, The Shadow barely discerned the outline of the penthouse against the sullen illumination of the city's lights, a glow that persisted despite the driving storm. The Shadow noticed that the penthouse was situated at the front corner of the building on the side toward Park Avenue. Passing that corner of the building, The Shadow observed a small side entrance to the apartment building. He guessed its purpose. The door must be a private entrance to a special elevator that took visitors to Selbart's penthouse. Entering the doorway, The Shadow found a small entry; he saw the double door of an elevator shaft, beyond it a small, keyless door that looked like the entrance to a closet. The elevator doors were a half-inch apart, a glow showed between them. The elevator was here on the ground floor. The Shadow wedged the doors far enough to grip the inner lever. He opened the doors, saw that the small elevator was empty. Quickly, The Shadow stepped to the closet door and whipped it open. On the darkened floor, he saw a slumped figure in uniform, trussed and gagged. The man was the elevator operator. He had been treated like Timothy had been handled at Rythe's. The closet reeked of chloroform. There was no time to wait longer. The Shadow left the door open so that the bound man could get more air. He stepped aboard the elevator and closed the doors. There was only one control button, marked: "Penthouse." The Shadow pressed it; the elevator, one of a modern type, made the ascent swiftly. Reaching the top, The Shadow silently opened the doors, stepped quickly from the elevator, a drawn automatic in his fist. Lights were on in the penthouse, their glow was indirect and mellow. The soft light was like a pall. That effect was increased by the unearthly silence that seemed to dwell within these spaces. There was no need for The Shadow to tread softly as he crossed the floors of huge, hushed rooms. Thick-tufted Persian rugs drowned every footfall. Every doorway was heavily curtained; those draperies looked like lurking-spots for hidden watchers. The Shadow recognized the possibility of spying eyes. He adopted a course that allowed for them. As he entered each room, The Shadow edged along the wall, his motion barely visible against dark oak panels. At each curtain, he performed a quick sweep with his gun; a move of the drapery, the muzzle jabbed behind it. Any hidden watcher would have been caught completely off guard, but The Shadow found no lurker. He came to the last of several doorways; frisked the curtains and stepped across the threshold. The Shadow had reached a square-lighted room that served as Selbart's library. There, The Shadow stopped. ON the floor lay a portly body, sprawled face downward. The figure was attired in a dressing gown that had pressed upward, high above the sprawled man's neck. It did not, however, cover the bald pate that showed above a fringe of thin, dark hair. Light glistened from the smooth bald head. The reflected glow was purple. The dye of death had tinged the skin that covered the sprawled man's skull. Stopping, The Shadow rolled the body sidewards. He recognized the pudgy small-eyed face that he saw. It was the fat, piggish countenance of Horace Selbart; but it had retained only a mere semblance to the photograph that The Shadow had seen in to-day's newspaper. Selbart's face was completely purple. Its puffy features had gained in size. His small, deep-set eyes were still tiny in proportion to the rest of his face, but they had definitely enlarged. They looked like purple agates that had been poked into the fatty sockets that held them. While The Shadow stooped, his hand upon the dead man's shoulder, a clock whirred in another room; then chimed the quarter hour. The Shadow had uncovered this case of the purple death at exactly half past ten. Letting the body sag face downward on the floor, The Shadow made a brief survey of the room. Little had been disturbed, but The Shadow noticed one spot where books had been removed from a shelf and clumsily replaced. Taking out the books, he saw an opened panel in the wall beyond. Some one had slid back the woodwork to reveal an open space that served as a small, shallow wall safe. There were papers visible; The Shadow examined them. Some were promissory notes, made out to Selbart. Several were signed by gamblers; but two bore the names of prominent New York artists; another was signed by a man who had recently acquired a large theater near Times Square. Others were letters. One was from a man who wanted money to open an abandoned gold mine; two were from inventors, one mentioning a new automotive device; another described the merits of a special process for taking motion pictures in natural colors, which would cut production costs below those of existing methods. The Shadow replaced the papers. He put the books back as he had found them. He looked at Selbart's body. The Shadow's lips phrased a whispered laugh, solemn and mirthless. THE SHADOW had long known that Horace Selbart had other interests than the precarious game of running gambling establishments. Being a multimillionaire, Selbart had always had plenty of money to invest. It was not surprising that he had figured in various types of transactions, for Selbart had always preferred to keep himself technically within the law. That, in a sense, had been his most pernicious practice. Selbart had backed many shady deals; his process was always to deal with a lone individual. Often, when gambling establishments had been raided in various cities, the proprietors had squealed that Selbart was the actual owner. None had ever proven that claim. Invariably, they had taken the rap themselves, because they could furnish neither witnesses nor written evidence. Selbart's own gaming establishments were always located in cities where the laws were lenient. The Shadow had suspected Selbart's past game; but had not interfered with it, for the big time gambler had been dealing with rats of his own ilk. He had also suspected Selbart's simple method. Selbart had simply advanced the gambling proprietors all the money that they needed; and in return, received promissory notes far in excess of the amount he gave them. If the men made out well, they were quite willing to pay their silent partner from the profits, even though he doubled or tripled his investments. If the game went sour with any of the gamblers, Selbart never produced the notes. Arrested gamblers went to the penitentiary, but did not have to pay their debts. What The Shadow had not suspected was that Selbart had used this method in dealing with persons who offered him legitimate opportunities to make money. Artists, theater men, inventors; all had pawned their future in the hope of getting a start. Selbart, cannier than the man with whom he dealt, had only advanced cash to those who he felt positive would gain success. The Shadow stepped back to Selbart's body, rolled it face upward. He studied the body closely, observed a small but deep gash on the heel of Selbart's hand. Closely, The Shadow pictured how the gambler had died. Some visitor had come to discuss the matter of an invention, probably bringing a model that Selbart had seen before he went to Europe. When Selbart had taken the object, a hidden spring had snapped, to jab a knifelike point into the gambler's pudgy hand. That cutting device had been loaded with the poison that delivered the purple death. The opening behind the bookcase indicated that Selbart had himself removed the documents that pertained to the invention - letters and promissory notes - to discuss them with his visitor. The killer had taken those documents away with him, but had not lingered to search the library for papers that pertained to other persons. Probably the murderer had not guessed that Selbart kept such documents at the penthouse. Having the papers that he required for himself, the killer had preferred rapid departure. CALMLY, The Shadow turned Selbart's weighty body face downward, so that it took its original position. As the form settled on the floor, The Shadow spied a tiny bluish object that pushed from beneath the dead man's shoulder. With gloved hand, The Shadow picked up the object. It was a stubby, blue pencil. The pencil was a round one; it was thicker than most. It was topped with a metal ring, but was not equipped for an eraser. The lead, like the painted surface of the pencil, was blue. Under usual circumstances, the pencil could have been classed as ordinary, although it differed from most standard makes of blue pencils. This pencil, however, was doubly important. Not only did it appear to be an object Selbart's murderer had dropped; the pencil was the exact mate of one that The Shadow had seen before, less than an hour ago. It was identical with the blue pencil in Lenger's box of chess clippings. Carefully, The Shadow replaced the pencil beneath Selbart's shoulder. Rising, he stood motionless while he viewed the dead man's body. Again, The Shadow delivered a whispered laugh. He had found a repetition of a former circumstance. There had been odd clues at the scenes of earlier murders: a fountain pen, a shirt button. Better clues had come with later deaths: a chess clipping and a blue-penciled memo with the letter "L." Despite the cleverness with which the purple deaths had been delivered, some odd clue had been left behind on every occasion. The Shadow knew that Joe Cardona had stolen the clipping and the memo. But Cardona, strangely vanished, would not be here to find the final clue. This time, The Shadow had discovered a clue before the law had opportunity; but he wanted to witness the reaction that would come when the clue reached the law. There was one way to accomplish that; namely, to summon the law to the scene of death. The higher up The Shadow went, the better the result would be. There was one man who would come here hot on the trail, if properly summoned. That man was Commissioner Ralph Weston. The Shadow's next move would be to reach him. With that decision, the cloaked investigator turned and strode silently from the room of purple doom. CHAPTER XIII THE LIPS THAT FAILED WHEN he had descended by Selbart's private elevator, The Shadow took another look at the gagged elevator operator. Fresh air had partially revived the prisoner; but the man's brain was still too clouded to sense happenings about him. The Shadow was satisfied, however, that no injury had been sustained, the man's stupor was due entirely to the effect of chloroform. Enough clear air had filled the closet; so The Shadow again closed the door with the prisoner inside. Reaching his cab, The Shadow ordered Moe to drive him to Professor Murkden's. On the way, The Shadow gave instructions regarding a call to Burbank. Arrived at Murkden's, The Shadow observed that Weston's limousine was gone; however, some lights still showed from the gloomy windows of the chemist's residence. The Shadow alighted. Moe pulled away. A servant answered The Shadow's ring at the front door; but he was not met by a cloaked visitor. The Shadow had resumed the guise of Cranston; he was wearing gray overcoat and hat. The servant recognized him as Lamont Cranston and ushered him into the reception room. The menial went to summon Professor Murkden. The stoop-shouldered chemist arrived from the laboratory. He greeted his visitor, then cupped one hand to his ear when The Shadow inquired regarding Weston's whereabouts. Catching his visitor's query, Murkden explained that Weston had gone to the Cobalt Club. "The commissioner expected you at nine o'clock," stated Murkden. "When you did not arrive, he became impatient. He went to the club almost immediately." "I thought that he would remain here quite a while," returned The Shadow. "Didn't he come to talk over blood tests with you?" "He had already received my report on the blood tests." "That's right. You established Rythe's death as occurring at eight-thirty, the same as Tabor's." The professor nodded, then added: "Commissioner Weston was disturbed because Inspector Cardona is missing. He was also quite incensed at a man who came with him here to-night." "You mean Courtney Grell?" "Yes. He left before my lecture was finished and did not return. I am to notify the commissioner if Grell comes back here. I believe that he intends to order Grell's arrest." THE SHADOW made his departure. Outside the house, he strolled for the corner, pausing every now and then to look for a cab. Moe's taxi showed up suddenly. The Shadow boarded it. He told the driver to take him to the Cobalt Club; then to call Burbank again. As The Shadow had arranged it, Burbank was to call Murkden's if The Shadow did not come out of the professor's house. Moe, cruising by, was to inform Burbank if The Shadow remained at Murkden's. Since The Shadow had come out of Murkden's, Burbank would still be waiting for the final order. This time, Moe would relay the order to call the Cobalt Club instead of Murkden's. At the club, The Shadow found Weston in a fumy mood. Searchers had been unable to locate Cardona; but that was only one reason for the commissioner's indignation. Weston was particularly aroused because of Grell. His mental state fitted with what Murkden had said. "Grell is gone, Cranston!" shouted Weston, to The Shadow. "The rogue walked out on me, in the midst of Professor Murkden's lecture. His actions have aroused my suspicions." "Of what do you suspect Grell?" queried The Shadow. "Of murdering Tabor and Rythe? Or of abducting Cardona?" "Either. Or both. Yet the fellow puzzles me. He had won my favor; it would have been good policy for him to retain it. Instead, he did the worst thing possible. He had no excuse for leaving Murkden's without my permission. However, he will answer for his indiscretion. I have just telephoned headquarters, telling them to send two plainclothes men to Grell's hotel and bring him here." The Shadow repressed a smile. Again, Weston was showing bad logic. If Grell returned to his hotel at all; it would be evidence of the man's innocence of murder and abduction. However, The Shadow expected Weston to forget Grell for the present. He saw an attendant coming to summon the commissioner to the telephone. Weston went to answer the telephone call, remarking that it might be news about Grell. When he returned, he was excited. As he had done the night before, he motioned his friend Cranston to come with him. They hurried outside and boarded Weston's limousine. The Shadow anticipated the direction that they took. The Shadow knew that the telephone call had come from Burbank; that the contact man had anonymously tipped off the commissioner to the fact that matters were not right at Horace Selbart's. Weston gained full evidence of that when he and The Shadow reached the gambler's apartment house. A patrol car was there ahead of them; the officers had found the elevator man in the closet and were arousing him. Weston had no time to wait until the prisoner's stupor ended. He ordered an immediate trip upstairs. The Shadow accompanied the commissioner in the little elevator, which was crowded to capacity. With them were two bluecoats, a pair of headquarters men, a police surgeon and the manager of the apartment house. THEY found Selbart's body as The Shadow had left it. One look at the gambler's dyed bald head told Weston that Selbart was another victim of the purple death. Weston took immediate charge of the investigation. He ordered blood specimens to be taken at once to Professor Murkden's. Then he began to go over the ground that The Shadow had already covered. Weston found the blue lead pencil as soon as the body was moved at his direction. The clue intrigued him. The commissioner expressed the belief that it might lead somewhere. He found nothing else, however, until The Shadow casually pointed out the disturbed books on the shelf. It was then that Weston uncovered Selbart's papers. After a deliberate inspection of the documents, Weston formed the conclusion that The Shadow had already drawn. Enthusiastically, he developed his version of the theory. "Some one came here to see Selbart!" exclaimed Weston. "Some one to whom he had loaned money. A person who felt himself swindled; unfairly treated. Selbart produced papers - one most certainly was a promissory note - and the visitor saw a chance to seize them." "Quite likely, commissioner," agreed The Shadow. "Of course, the killer came here with the deliberate intent of murdering Selbart." "Not necessarily," objected Weston, who usually disagreed with any one who made prompt editions to his theories. "The murderer might have performed his crime through sheer desperation." "Odd then, that he should have come equipped with some device that delivered the purple death." Weston chewed his lips. "That is true, Cranston," he admitted finally. "Yes. The murder must have been premeditated. But the motive is plain. The man had been swindled by Selbart." "I suppose then," remarked The Shadow, "that he was swindled by many other persons. Seven to be exact." "What seven?" "The previous victims of the purple death." Weston considered. His face showed perplexity. "You're right again, Cranston," he decided. "It doesn't fit, does it? The other purple murders looked like thrusts against innocent parties. This one is quite the reverse. It baffles me. However" - Weston's eyes showed one hopeful gleam - "we can at least establish the time at which Selbart died. He only arrived in New York this afternoon; his blood will be fresh enough for another analysis by Professor Murkden." A patrolman arrived to announce that the elevator operator had recuperated, but that he was too sick to bring upstairs immediately. Weston decided to go down to the ground floor. The Shadow accompanied him. When they stepped from the elevator, they saw the operator propped on a chair near the outside door. The released prisoner looked very white; the after-effects of the chloroform had sickened him. He was wrapped in a big overcoat, with a blanket around his legs so that he could benefit from fresh air whenever the door was opened and at the same time could avoid a chill. "IT was at eight o'clock they got me," informed the man. "A couple of huskies wearing masks. They rang for me and I came down. They piled on me so quick I didn't have a chance." "Eight o'clock," mused Weston. "Then this could have been another eight-thirty murder like the others. This time, the murderer had to send some toughs to clear the way for him. He must have another rowdy working for him like Slook Howdrey. Yes, that fits. It could be the same group that captured Cardona earlier." The commissioner eyed the operator; then demanded: "Why were you up at the penthouse with the elevator?" "I had just delivered a note," explained the operator. "A messenger brought it for Mr. Selbart." "You saw Selbart alive, at eight?" "Yes, sir. There were others, too, that must have seen him just before then. His niece and three friends. I brought them down just a little while before the message came. They were going to the opera." Weston consulted his watch. It was just eleven o'clock; not yet time for the party to return. "We'll investigate that message," decided Weston. "It could have come from the murderer; perhaps to tell Selbart to expect him later. The murderer probably took the message away from him. I wonder" - Weston paused, reflectively - "I wonder if Grell could be in on this. He could have sent the message. It might explain why he hurried away from Murkden's -" Weston stopped short. The door was swinging open. In from the snowy night came two headquarters men, dragging a prisoner between them. Each had locked his own wrist to one of the prisoner's. The man was helpless as they hauled him. Face to face with Weston, the fellow glared as the commissioner ejaculated his identity: "Courtney Grell!" Grell grimaced sourly. His sallow face showed indignation; but with it, there was an air of triumph. "Hello, commissioner," greeted the sallow man. "So they brought me to you after all. I thought it was a stall, when they grabbed me at my hotel and said you wanted to see me. That's why I put up an argument." "You'll put up an explanation," snorted Weston. "You'll tell me why you left Professor Murkden's lecture without my permission." Grell's eyes opened. His lips phrased a laugh. "SO that's it!" he exclaimed. "Say - I didn't think you'd get so huffy over a little thing like that. You can't arrest me for just leaving Murkden's -" "I can arrest you for murder." "Whose murder?" "The murder of Horace Selbart, which occurred this evening. Also for the murder of Trumbull Rythe, last night. The fact that you found Rythe's body did not prove that you first visited his home at ten o'clock. Similarly, unless you have an alibi for this evening, you will be in a bad way, Grell." The sallow man winced. The Shadow knew the reason. Grell's only alibi for nearly an hour after leaving Murkden's would be Louis Lenger. Knowledge of that fact made Grell shaky. He sank back. The plain-clothes men jerked him forward with the handcuffs. "So we've found the murderer," accused Weston, as he noted Grell's expression. "Take him to headquarters. We'll grill him there -" "No, no, commissioner!" Grell's tone was excited, pleading. "I'll - I'll talk. I'll tell you what you want to know - who the murderer really is. But I never met the man before to-night. But take the handcuffs off me -" "Take him away," roared Weston. Then, suddenly: "No, wait! Has he a gun on him?" The plain-clothes men shook their heads. "Remove the handcuffs," ordered Weston. "Grell, I'll give you five minutes to come clean. You claim that you know who the murderer is. Tell us all that you know about him." Grell grinned wisely as the handcuffs came off. He rubbed his chafed wrists; then thrust a hand into his overcoat pocket. One of the headquarters men grabbed for his arm. Grell's hand came out bearing a fresh package of chewing gum. The headquarters man looked sheepish while Grell chuckled and opened the pack of gum. "Come, Grell," insisted Weston. "Your five minutes have begun." "I can tell you everything in three minutes," promised Grell. "So I'll wait two, commissioner, just to put you in the right mood. When I've told you my story, you'll be ready to hand me a medal. I'll have all the time I want. You'll be willing to listen to anything I tell you." Deliberately, Grell began to chew his stick of gum. Shoving the wad to the side of his mouth, he eyed Weston and spoke methodically. "Inspector Cardona held out a couple of clues," announced Grell. "The first was a clipping from a newspaper, that showed a chess problem. He found that at Tabor's; at least I think he did. I'm guessing at that part of it. "The second clue, I'm sure about. It was a memo signed by the letter 'L.' Cardona found it at Rythe's, where I'd seen it ahead of him. Cardona came to see me this afternoon. We talked about that memo then. Cardona knew a lot; too much for his own good, because he wasn't smart. "To-night, I picked up where Cardona left off. I found out about the first clue; knowing the second. I hooked the two and they led me straight to the murderer. I went to see him, like Cardona did; but I was smarter. I came on my own; not as a representative of the law." "If you know who the murderer is," bellowed Weston, "tell us! I give you one minute, Grell!" Headquarters men gripped Grell's arm, ready to clamp the bracelets again if Weston gave the order. Anger showed on Grell's face; then his lips formed a smirk. "The murderer's name?" remarked Grell. "Certainly, I shall tell it to you, commissioner. Of course, it begins with an 'L' -" A SUDDEN choke broke Grell's voice. He gulped, slumped in the arms of the headquarters men. They yanked him upright. Like Weston, they thought it was another bluff. Only The Shadow realized the real cause. Springing forward, he gripped Grell's neck and chin; tilted the man's head forward with a snap. Grell's jaws spread, his wad of gum plopped from his mouth and struck the stone floor of the entry. Yet with all his speed, The Shadow was too late. As he released Grell's head, the sallow man's chin sagged downward. His body sank to a dead weight, dragging forward the men who gripped him. A death gasp hissed as Grell's jaws clamped. Weston gave a startled shout. The headquarters men saw why, for they were looking at Grell's face. A rush of blood had come to that sallow countenance; as it spread, its crimson hue darkened. Grell's features enlarged, his eyes bulged. Over all came an indelible dye. Grell's staring face, his limp hands, were turning purple. The transformation was a swift one that could not be revoked. The men who gripped him lost their nerve; they released their burden. Grell toppled hard upon the floor, rolled over face upward, as men shrank back, avoiding him like they would a victim of the plague. Only The Shadow did not recoil. He was stooped beside the body, Grell's head raised in his hands. His face retained the calm composure of Lamont Cranston, but his eyes - which none could see - held a burning glint as they studied the death-frozen countenance beneath them. The Shadow was viewing a new victim of a powerful murderer; a victim whose name was not on the list, but who had been added through necessity. The name of Louis Lenger would never be spoken by Courtney Grell. Sallow lips had failed at the last moment. Again, the purple death had claimed a victim, this time in the very presence of The Shadow! CHAPTER XIV THE SHADOW'S TESTS POLICEMEN carried Grell's body up to Selbart's penthouse. They handled the corpse gingerly. Sight of the purple death in actual progress had unnerved these witnesses. Only The Shadow's bold handling of the body had stiffened the men to whom Weston gave the order. The commissioner, however, decided to come up on a second trip, claiming that the elevator was too crowded. That second trip included The Shadow and the officers who had brought Grell from the hotel. Weston questioned his men during the ride; they mentioned that they had merely frisked Grell for weapons and had not inspected other contents of his pockets. The incident of the chewing gum made Weston decide that there might be important finds on Grell's body. Reaching the penthouse, detectives began a search of Grell's clothing. For a while it looked as though Weston's guess was wrong; then came a discovery. Deep in an inside pocket of Grell's overcoat, a detective found a sealed manila envelope. On it were penciled notations, the names of Talbot and Rythe, with the dates when their bodies had been found. "Cardona's writing!" exclaimed Weston. "Let's see what's in here!" He ripped open the envelope. Inside, he found two items. One was the chess clipping that Cardona had picked up at Tabor's. The other was the memo that Joe had found at Rythe's. Weston read the notation with the signature that consisted solely of the letter "L." "Grell told us the truth about these," decided Weston, solemnly. "But he said that they were Cardona's clues, not his own. How did Grell happen to get them?" Weston put the question to The Shadow; but before he received a reply, the commissioner had another inspiration. "Look!" he exclaimed, "The memo is in blue pencil. Here are two clues to begin with - and we have a third! The blue pencil that we found here with Selbart's body!" The Shadow made no comment. He had recognized the blue pencil link from the time of his first visit to the penthouse. Seated in a corner of the room, The Shadow merely watched Weston's expression. It was plain that the commissioner was piecing facts together. His square face looked grim, then his lips formed a convinced smile. Looking about, Weston saw headquarters men standing expectantly, as if waiting for him to solve the mystery. He noted The Shadow sitting silent. Weston's smile tightened. "Tell me, Cranston," he suggested, "what do you make of these facts? I want your whole opinion. I would value it highly." The Shadow saw that Weston was asking for an opinion merely as a build up to his own. Therefore, when he answered, he confined his remarks to a simple statement. "GRELL was right," asserted The Shadow. "Cardona found the two clues: one at Tabor's; the other at Rythe's. Crooks seized Cardona because he pushed those clues too rapidly. Grell had an inkling of the situation. He looked for a man whose name began with 'L' -" "We heard all that," interrupted Weston, impatiently. "What I want to know, Cranston, is if you think Grell actually met the murderer to-night." "Grell must have met the murderer," returned The Shadow. "Otherwise, the two clues would not have been in Grell's pocket." "You think the murderer gave the clues to Grell?" "Not necessarily. He could have placed them in Grell's pocket at a time when Grell had taken off his overcoat. That is when he also placed the chewing gum in Grell's pocket, substituting it for a pack that Grell already carried." There were nods from the listeners. They remembered how The Shadow had been the first to recognize that Grell was chewing poisoned gum. Weston saw the nods. His smile increased. "Your theory is good, Cranston," declared the commissioner, "but it has one weakness. Since the murderer abducted Cardona because he had the clues, why should he have returned those same clues through Grell?" "You would like the answer?" Weston smiled and shook his head. "There is no answer, Cranston," he declared. "Grell's story was a lie. We do not need to search for a man who plays chess and whose initial is 'L.' We have already found the purple killer - and there he is." Dramatically, Weston pointed to Grell's body. While The Shadow smiled, others stared astounded at the commissioner's new theory. "Grell committed the murders," asserted Weston. "When he realized that he was leaving clues behind him, like a fountain pen and a button, he became worried. The chess clipping that he accidentally dropped was actually a mistake. It worried Grell more than ever. "So he purposely left the memo with Rythe's body. It was a note that he had probably picked up somewhere. Cardona, however, was smart enough to trace both the clipping and the memo to Grell. That was why Grell abducted Cardona; and took the clues from him." Weston paused. He was coming to the crux of his theory. "Though he failed to bluff Cardona," declared the commissioner, "Grell believed that he could trick me. He tried it to-night; thought that he had won my confidence and could leave Murkden's without arousing my suspicion. Nevertheless, Grell was prepared for a last resort. "His weapon of death was the purple poison. He knew that in an emergency, he could escape the electric chair by suicide. Downstairs a short while go, Grell knew that his game was through. He made a last bluff, saw that it was failing. He did not even produce the clues, with some cock-and-bull yarn to explain how he acquired them. He took that stick of chewing gum and ended his life in our presence." Listeners had new nods. These were in support of Weston's theory. The Shadow arose; spoke quietly to the commissioner. "I SUPPOSE, however," said The Shadow, "that you would like to know the identity of the man who signed himself 'L.'" "Why?" demanded Weston. "The case is closed. I shall tell the press that Grell was the murderer. Grell was a crook at heart. Let us hope that his underlings will weaken; that Cardona and the missing detectives may still be alive. The fact that we have trapped the master murderer may lead others to release them." "Yet 'L,' if you found him, might tell you facts concerning Grell." "Bother 'L.' He is simply the herring that Grell drew across our path. Of course, we shall try to trace the clipping, the memo, the blue pencil; as a matter of routine. But I can assure you, Cranston, that this supposed man 'L' is either imaginary or unimportant." The Shadow shook hands with Weston as though congratulating the commissioner on his theory. He departed; a detective took him downstairs in the elevator, remarking on the way that the commissioner "sure knew his stuff when he got started." Outside, The Shadow rode away. Later, he arrived at the sanctum. There, The Shadow's hands busied themselves beneath the bluish light making notations in an ink that faded after each thought had been inscribed. To-night, The Shadow had been willing to give Commissioner Weston some facts regarding Courtney Grell. Since Weston had refused to accept them, The Shadow intended to pursue those facts on his own. He did this with the knowledge that emergency existed. Though he would have prevented the deaths of Horace Selbart and Courtney Grell, The Shadow had few regrets concerning them. Both men were crooks; that stood proven. Selbart's death marked the last that the purple killer had listed. Grell's death - together with his actions - had sufficient explanation. Many of Grell's past activities had approached blackmail. To-night, Grell had seen a chance to deal in that gentle art. Picking Louis Lenger as the purple murderer, Grell had made friends with the chess expert. Keeping in right with the law, Grell had hoped to press that acquaintance, to wind it up with a demand of cash for keeping silence. That was why Grell had not intended to turn his findings over to the law. The fact was obvious to The Shadow; he believed that others could have seen it, even though Commissioner Weston had not. One, however, who was capable of spotting Grell's game was the purple murderer. Therefore, the murderer had planted the clues that had been taken from Cardona. He had also placed the chewing gum in Grell's pocket. He had figured that Grell would chew the gum before finding the envelope that was so deeply tucked away. Once Grell died, the clues and the chewing gum would both be found. The purple murderer had disposed of Grell because the sallow man was a trouble-maker. It had worked out as the murderer wanted; circumstances, however, had chanced to make the finish a close call. Grell had not taken a stick of chewing gum as soon as the murderer expected he would. Thus Weston's men had found their chance to grab him. When had the goods been planted on Grell? Not at Lenger's. Grell had removed his overcoat there, but The Shadow had been on watch. The planting had come later, after Grell went out with Lenger. Therefore, the answer lay in learning partly how long Grell had been with Lenger, and just where Grell had gone. Why had the murderer sent back the clues by Grell? The answer was that he wanted the police to have them, that he considered those clues insufficient, in themselves, to incriminate him. The murderer believed that the clues would mislead the law. The only break had come when Cardona and Grell had noticed Lenger's letter to the chess column; but the newspaper that printed that letter was now one day old. Weston would not search the back files; particularly since he believed Grell a suicide. The murderer had made a good guess as to Weston's actual reaction toward Grell's death. THE bluish light went out. Soon afterward, a light appeared in a room that was walled with shiny black. The room was a laboratory; all its equipment was of that same ebony hue. Here, The Shadow returned to the task that he had originally scheduled. From his cloak he brought the slides that showed the blood clots. He produced the test tubes that contained samples of Professor Murkden's lettered compounds. He begin an analysis of the liquids. After an hour, The Shadow came to the conclusion that the chemist had done an exacting task. Compound "F," when compared with the attested formula, had the expected elements of the purple poison. There was one way to make a final proof. The Shadow had gained important evidence when he had seen Grell die. He had witnessed the actual effect of the purple death; no longer did he need to rely solely on post-mortem data. From a chest in the corner, The Shadow brought a guinea pig. He gave it an injection of Compound "F." The result was instantaneous. A tinge appeared upon the whiteness of the guinea pig; became a purple. As the dye increased, the cavy fell dead. Immediately, The Shadow began a series of blood tests, at timed intervals. One hour later, he injected the compound into another guinea pig, thus starting a new sequence of blood tests. At regular intervals, The Shadow continued the tests and made microscopic examinations. It was not long before The Shadow discovered an important factor. The tests were conforming to the findings of Professor Murkden, but with one exception. The professor's tests - according to the data available - showed a slower rate of coagulation than did The Shadow's experiments. This meant that The Shadow's test made one hour after the guinea pig's death corresponded to the professor's test at the end of two hours. From then on, the tests corresponded, but always, The Shadow's slides retained that one hour advantage. This was singular as The Shadow was using the chemist's own compound. Professor Murkden's tests had shown that victims of the purple death had died at half past eight, in accordance with the time that Joe Cardona had set them. The Shadow's tests proved The Shadow's own theory that the victims had died at half past nine. To account for this discrepancy, The Shadow decided to make another test. He had more guinea pigs available; but he had used up his supply of Compound "F." The Shadow decided upon departure. He extinguished the lights of the laboratory. Half an hour later, The Shadow arrived at Professor Murkden's old house. The building was completely dark. Silently, The Shadow effected entry into the professor's basement laboratory. Shading the windows, The Shadow turned on a single light. He took the large bottle of Compound "F" from its shelf; began a careful analysis of a small quantity. It tallied exactly through The Shadow's own test of the compound. The Shadow was ready to make a new blood test. He went to the corner and obtained one of the professor's guinea pigs. The Shadow injected the compound into the guinea pig. He watched the result. The guinea pig seemed loath to release its hold on life, but the effects of the deadly compound could not be resisted. Gradually the chemical mixture overpowered it. The Shadow began to study the blood coagulation. After the first two tests, he discovered that they fitted Murkden's analyses and not his own. Although the compound was identical, the coagulation proved slower. Taken as an example, this test bore out the professor's tabulations. The Shadow ceased his work at the end of the second hour. He put the guinea pig with the other dead ones that had perished in the interests of science. He extinguished the lights in Murkden's laboratory and made his exit by the window. The storm had ceased. Dull dawn was knifing through the clouds that still clustered above Manhattan. The Shadow saw lights in the third floor of Murkden's house. The servants were rising early. To-day Murkden had more work to do, he must test the blood of new victims - human ones - who had died last night by the purple death. No streaks of dawn revealed The Shadow. He was enshrouded in the darkness that still clung in the thoroughfares where traffic had not commenced. The Shadow's task had been completed. He could sleep during the coming day, leaving the laboratory work to Professor Murkden. Night perhaps, might bring a new thrust of the purple death; but it would be hours yet before the purple killer moved abroad. Before that time arrived The Shadow would be ready to delve more deeply into matters that concerned Louis Ledger. Once those were settled The Shadow could thwart the purple killer. More than that, in his coming quest, The Shadow saw opportunity to remove the pall of mystery that enshrouded the unsolved disappearance of Joe Cardona. CHAPTER XV LINKS TO CRIME IT was seven-thirty the next evening. Commissioner Weston was at the club, beaming enthusiastically over a newspaper as he spoke to his friend Lamont Cranston. "The press has accepted my views," announced Weston. "Grell is recognized as the purple murderer. The chain of death is ended. Our next task is to find Cardona and the missing detectives." "It is time that they were located," observed The Shadow. "But just how do you intend to find them, commissioner?" "Through a complete check-up of Grell's affairs. We have searched his suite of offices and his hotel room. I believe that we shall unearth some important clues." "Even though you have found none so far." Weston was irked by the quiet remark. Though the commissioner firmly believed that Courtney Grell was the purple murderer, he knew that he was short on evidence. Search had as yet produced no expected results. Grell's effects had lacked any documents that pertained to murdered men; and the police had found neither weapons nor supplies of the purple poison that could have been in Grell's possession. "We learned much from Professor Murkden's tests," declared Weston, suddenly, hoping to drop the subject of the futile search at Grell's. "He estimated eight-thirty death in the case of Tabor and Rythe. To-day, he made blood tests to learn when Horace Selbart died, and he found -" "Eight-thirty again." Weston stared at The Shadow's interruption; then laughed. "Good guesswork, Cranston," he remarked. "Since Tabor and Rythe both died at eight-thirty, you figured that must be the usual time of action. Yes, you are right. Professor Murkden proved conclusively that Selbart was slain in his penthouse at exactly half past eight last night." Weston was about to leave the club. He extended an invitation before departure. "I am going to Professor Murkden's usual lecture," stated the commissioner. "Would you care to accompany me, Cranston?" "I have another appointment," replied The Shadow, "but since you are going to Murkden's, I would recommend that you have him perform another test." "Another test?" "Yes. To find out when Courtney Grell died." "But we saw Grell die! It was after eleven o'clock, when my men brought him to Selbart's. What use would there be to make a blood test in Grell's case?" The Shadow smiled; then gave the reason. "Since you know when Grell died," he stated, slowly, "tests of his blood would serve as a basis for exact computation of the time element. From Grell's case, you can learn if Murkden was right in his calculations of the previous cases." "I never thought of that, Cranston," admitted Weston. "Nor did Professor Murkden. I shall speak to him about the matter to-night. Of course, the tests are actually unnecessary, for Murkden's Compound "F" closely resembles the purple poison; hence his calculations can not be in error. Nevertheless, a test of Grell's blood would silence any doubtful persons. Your suggestion is a good one, Cranston." As soon as Weston had gone, The Shadow left the club. Riding southward in a taxi, he indulged in speculations regarding the purple death. THE SHADOW'S own tests had shown an hour's variation from Murkden's. They indicated that Tabor and Rythe had died at nine-thirty; therefore, Selbart's death could also have occurred at half past nine, since it tallied with the others. Still, there was another element to be considered: that was the last test that The Shadow had performed, in Murkden's laboratory instead of his own. Using the same formula and the identical methods, The Shadow had found that his last test tallied with the professor's. If that test stood, eight-thirty would have to be considered the time of death. Nevertheless, The Shadow was satisfied despite the odd discrepancy. Whatever his reason, it was known to him alone. At present, The Shadow had another matter to consider. It was plain that the chain of murders involved some important invention that had been backed by Horace Selbart. Some one had acquired the invention by murdering the inventor; then killing other persons who knew about it or who could have blocked its commercial success. Among the dead, perhaps, were persons whose connection with the matter had been peculiarly remote. Selbart had been left to the last. The murderer had decided that the gambler would hear little of the purple death while en route home from Europe; that whatever he did hear, he would keep to himself because of his own hidden connection. Reaching Selbart had been an easy task. The murderer had probably posed as a person whom Selbart would not fear; it was also likely that he had promised to divulge valuable facts that Selbart would want to hear alone. Since an investigation of the victims would prove too long a task, The Shadow had decided to concentrate upon living persons. Louis Lenger was important. Clues, properly linked, pointed directly to him. Should the law link those clues as The Shadow had, Lenger would be promptly arrested. Yet the law, if it found Lenger, would be blocked by what it had already learned from Professor Murkden's tests. Those tests showed that the murderer had delivered purple death at half past eight, on every tested occasion. To pin the murders on Lenger, the law would have to prove that he had been at large at half past eight on at least one of three successive nights. The Shadow, had overheard Lenger tell Grell that he played chess every night from seven o'clock until nine, with a friend named Howard Feasley. Lenger, if arrested, would depend upon Feasley for an alibi. If that alibi could prove as acceptable to the law as Murkden's blood tests had been, Lenger would never be convicted. Hence The Shadow's first step on this important evening was to look in on Howard Feasley. NEARING the outskirts of Greenwich Village, The Shadow left the cab. He soon found the address which was listed with Feasley's name in the telephone book. At the front door, The Shadow noted name cards that indicated that the house was divided into improvised apartments. Feasley's bore the number "3"; it was evidently the top floor of the residence. Skirting the block, The Shadow came to the rear of the building. Looking up from the darkness, he saw that the top floor had a porchlike projection at the rear. The house next to Feasley's was empty. It also had a top rear porch. Cloaked in black, The Shadow worked at a rear door of the empty house. He found no difficulty with the simple lock. His entry effected, The Shadow used a tiny flashlight, found a stairway and went up through the empty house. Soon he stepped out on the rooflike porch at the back of the third floor. There was a separating wall between this porch and Feasley's; but The Shadow swung around it. The shift was a nervy one, for he swung outward above thirty feet of space, but the move was not difficult. It proved that it would be quite an easy matter for any one to visit Feasley's apartment by this unseen route. There was a door that led into Feasley's apartment; it was unlocked. The Shadow stepped into a darkened room. He reached a door at the front, opened it slightly and peered into a lighted room. There he saw two men seated at a chess board. One was Louis Lenger. The heavy man was bowed close to the chess board, stroking his chin, which was as stubbly as it had been the night before. Facing Lenger was a man who fitted the description of Howard Feasley. Frail of build, wan of countenance, Feasley was propped in an armchair. He was wearing a dressing gown and was well swathed with blankets even though the room was not chilly. Feasley's appearance indicated that he had gone through a long illness; but the man's smile, his keen interest in the chess game, were proofs that he was well recovered. Both Lenger and Feasley were too intent upon their game to suspect The Shadow's presence. Looking about the room, The Shadow noted that it was in good order. Probably Feasley had some one come to arrange it every day. One oddity, however, commanded The Shadow's notice. On a far wall of the room was a blackish square, covering a space that had once held a wall bracket. Evidently some electrical installment had been started and not completed. The important point, however, was that the black plate matched the square block that The Shadow had seen in the entry of Lenger's Twenty-sixth Street apartment house. A clock showed a few minutes after eight. A brief view of the chessboard told The Shadow that the players had just begun their game; that they were proceeding with slow, methodical tactics. It would be quite a while before they finished their game; perhaps it would have to be called at Feasley's nine o'clock bed hour. The Shadow waited no longer. He left by the route through the back of the building. He descended through the empty house, found a cab on a side street. Boarding the taxi from darkness, The Shadow quietly ordered the driver to take him to an address on Twenty-sixth Street. THE SHADOW had looked into the matter of Lenger's alibi; he had found that it existed. Lenger's presence at Feasley's fitted his statement that he played chess with the invalid between the hours of seven and nine. It did not, of course, prove that Lenger had been there the last three evenings. Only Feasley could have settled that fact. However, since Lenger was at Feasley's, he could not be at his own apartment. Therefore, The Shadow had opportunity to visit Lenger's. Such a trip had become important from the moment that The Shadow had observed the black plate in the wall. Such devices were not common. To see one in Lenger's entry; another on Feasley's wall meant a definite connection. When he reached the apartment house on Twenty-sixth Street, The Shadow avoided the entry until later. Instead, he went in by the rear door; took the stairway up to Lenger's. Once inside the untidy apartment, he began a rapid inspection. All the bits of evidence that The Shadow had noticed last night were undisturbed. Looking through a bureau drawer, The Shadow uncovered two other items. One was an old box that had once contained a fountain pen; another was an old, frayed shirt that had one button missing. The absent fountain pen could be the one that a detective had found on a murder scene. The buttons of the frayed shirt were identical with a photograph that The Shadow had seen of the celebrated "button clue" that had been picked up by another missing dick. It was among some papers in another drawer that The Shadow found an item which he regarded as more important than all the rest. This was a certificate of title made out to Louis Lenger. It named Lenger as the owner of this apartment house in which he lived. This discovery fitted with the picture that Lenger gave the world concerning himself. Lenger was ostensibly a man with moderate income, living on the interest of investments. One of his assets was the modest apartment house. Unable to rent the fourth floor apartments, Lenger had moved into one. Nothing could have been more logical. It fitted also with a definite theory that The Shadow had formed. When Joe Cardona had started on his trip to Lenger's, The Shadow had followed him. The Shadow had seen no other trailer. Therefore, The Shadow had divined that Cardona must have run into trouble close to Lenger's. He had considered it a likelihood that Joe had been captured in the apartment house itself, but The Shadow had avoided a detailed search while matters were requiring solution. There was one odd feature that would have perplexed an ordinary sleuth. That was why Grell had not been grabbed like Cardona. To The Shadow, that could be easily answered. His whispered laugh told that he knew why Grell had come and gone, to be handled elsewhere. That token from The Shadow's lips brooked trouble for the purple murderer. LEAVING the apartment, The Shadow descended to the ground floor. He found the elevator there, opened the door and peered into the car. It was his first view of the elevator's interior; it must have suited some theory that The Shadow had in mind. Closing the elevator, The Shadow found a stairway to the basement. He looked about, discovered that the cellar was a comparatively small one; that it showed a large expanse of heavy concrete wall that had evidently been installed to form a new foundation. Ascending to the first floor, The Shadow left by the rear door. He went to the front of the building, peered into the entry but did not pass the lighted threshold. Again, The Shadow viewed the black plate on the entry wall. Moving back, The Shadow edged into the darkness close to the building line. He had gained facts that he wanted; to them, he had added other possibilities. His thoughts were concentrated upon one matter that he had never forgotten - the disappearance of Joe Cardona. The Shadow knew that Cardona must have been quickly and efficiently captured; yet Joe had recovered promptly from whatever attack he had met. Although a prisoner, Cardona had managed to make two telephone calls soon after his capture. Those facts told The Shadow what would probably be encountered by any one who sought to follow Cardona's actual trail. It offered The Shadow the very challenge that he wanted; for he had guessed the route that Cardona had taken. The Shadow's plans were made. A quick trip to the sanctum, a prompt return, that would bring him here before nine o'clock, the time when Lenger usually left Feasley's. In the short interval that would remain, The Shadow would attempt to solve the riddle of Cardona's disappearance. That done, he would have another task ahead. For The Shadow foresaw that the purple death had not reached its limit. He had divined that a new murder would be necessary to the schemes of a master crook. Through quick thrusts, The Shadow planned to balk the vital move of the purple killer. CHAPTER XVI THE LAW LEARNS WHILE The Shadow was on the move, completing speedy plans, Commissioner Weston was complacently seated in Professor Murkden's lecture room. Though he had found Murkden's previous lecture an interesting one, Weston was bored upon this occasion. Murkden had passed the subject of blood coagulation; his remarks concerned chemical conditions that had but little bearing on the purple death. Had Weston felt in his present mood the night before, he would not have been piqued by Courtney Grell's departure from the lecture room. Last night, Weston had been tense; everything seemed important while he still sought facts regarding the purple murder. To-night, satisfied that the riddle was solved with Grell's supposed suicide, Weston felt that matters were monotonous. The commissioner wanted to talk with Murkden; to settle any minor details. He was anxious for the lecture to end. The professor must have noticed it. Instead of prolonging his lecture until nine o'clock, Murkden cut it short ten minutes before the hour. Disposing of the lecture group, Murkden greeted Weston. He conducted the commissioner to the laboratory. As Murkden was preparing a set of slides, one of his servants appeared accompanied by a police surgeon who had come at Weston's order. Murkden looked up from his projector and smiled. "Excellent, commissioner," observed the chemist. "I am pleased that you summoned a physician here. I am going to compare the slides that show the blood changes in all three victims. This demonstration marks the completion of my experiment. Therefore, I am glad that a qualified observer is on hand to attest my findings." The projector glimmered. On the screen, Weston and the physician saw four enlarged representations of blood specimens. They were labeled; the names showed on the screen: Tabor, Rythe, Selbart; below them, a slide that bore the title: "Certified Test." "The three upper slides," stated Murkden, "show blood specimens tested at precisely half past eleven on three successive nights. The certified test shows the blood condition of a guinea pig exactly three hours after death. It is identical with every other test performed with guinea pigs. "This proves conclusively that every victim of the purple death died at half past eight. Let me show you another set of slides. These show the blood condition a half hour later. Again, you will observe that they match." Murkden projected a new set. The later blood conditions were identical. The professor was about to introduce another set of slides when Weston stopped him. "Those are sufficient," declared Weston. "There is another matter that I should like to discuss with you, professor." Weston turned to the police surgeon. "Have you brought the specimens, doctor?" THE surgeon nodded. He brought a cardboard cylinder from his pocket, produced a corked bottle from it. "A specimen of Grell's blood," remarked Weston, reading the label, "taken at eight o'clock to-night. We should like you to test it, professor." Murkden looked puzzled, then remarked: "This seems superfluous, commissioner. You already know the time at which Grell died. A test is not necessary." "That was my original opinion," admitted Weston, "but it occurred to me this evening that a test of Grell's blood would serve as a final key to the others. Better than your tests with guinea pigs." Weston expected Murkden to raise an objection. He would not have been surprised to see the professor rare in indignation. Instead, Murkden shook his head sadly. "You should have thought of this before, commissioner," declared the chemist. "Or, perhaps, the blame can be placed upon me. Late last night, I was on the point of calling you, to ask for specimens of Grell's blood." "Why didn't you call me?" "Because I was satisfied with my formula. I was sure that Compound "F" contained every needed element of the purple poison. You agreed with that opinion. If I had called you, commissioner, you might have misunderstood my request for specimens of Grell's blood. You would logically have believed that I doubted my own tests." "True, professor. Yet a test of Grell's blood would have finally proven the correctness of your experiments." Murkden smiled. "My tests were already established," reminded the professor. "They were accepted and attested. Since you had expressed your full approval -" "I understand," interjected Weston. "The fault was mine, professor. However, there is still time to make a test with Grell's blood. He died after eleven o'clock last night. It is now nine o'clock - less than twenty-four hours since his death." "Too long an interval," returned Murkden. "I originally set twenty-four hours as the maximum limit for tests. Since my actual experiments with the blood of fresh victims, I have learned that the chemical changes reach their final state in twelve hours. Here are the attested experiments, commissioner." Murkden produced a sheet of typewritten notes. Studying them, the commissioner saw that Murkden's statement was correct. Weston shrugged his shoulders. After all, the idea was Cranston's, not his own. The commissioner decided that his friend should have thought of it sooner. PROFESSOR MURKDEN, meanwhile, was removing a slide from the projector. Weston saw no need for further demonstration. He motioned for the surgeon to leave; then turned to speak to Murkden. A ring of the telephone interrupted. Murkden put away the slide that he held. Methodically, the professor answered the telephone. The call was one that had been received upstairs and relayed to Murkden's laboratory telephone. Weston stood by impatiently while Murkden talked. The professor was having his usual difficulty hearing over the telephone. "Louder, please!" insisted Murkden. "Yes. The connection must be bad... Yes... I hear you... Wait. I shall write it down..." Murkden made notations upon a pad. Apparently, all was clear until he came to write a final name. "What's that?" he queried. "No. I can't catch the name... Wait a moment, please... You can speak to the commissioner... What's that? No, no. I am not the commissioner... You said you wanted to talk to him? I thought you simply asked if he happened to be here... Certainly. It would be better if you spoke to him... Hold the line, please..." Murkden turned around and nodded to Weston, who had strolled away impatiently. The commissioner paced over to the table; snatched the telephone as Murkden gave it to him. Weston's wrist tangled in the receiver wire. Angrily, he wrenched it free. "Hello... Hello..." A click came with Weston's words. The call was ended. Weston joggled the receiver hook. Finding the line dead, he hung up and glowered. "It must have been your man upstairs," snapped Weston. "He thought that when you finished talking the call was ended. Anyway, I was cut off. Perhaps the person will call again." "He gave me the message," reminded Murkden, passing over the paper with its notations. "I understood everything, except the last words. These notes, though, are meaningless to me." Weston read the notations: One dozen blue pencils. Azure Specials, Number 3. Purchased by Louis Lenger. Deedham Apts., Twenty-sixth Street. Other purchases, chess books. Company, Retail Stationers. "This is plain!" exclaimed Weston, in high enthusiasm. "We sent out a flier to all stationery stores, asking them to check on blue pencils that they had sold. Azure Special, Number 3, is the type of pencil that we found last night at Selbart's. The brand is obsolete. We thought that the purchaser might have bought some left-overs. "So a man named Louis Lenger bought those pencils! Wait! That memo at Rythe's was signed with the letter 'L.' That fits. Look at this, professor: Lenger bought chess books also! That covers the chess clipping that Cardona found at Tabor's." WESTON paused; pointed to the final notation on the list. "That was the name I couldn't understand," explained Professor Murkden. "The man on the telephone was trying to tell me who he represented. It was some-one and company, retail stationers; but I couldn't catch the actual name of the concern." "Which doesn't matter," put in Weston. "Our flier went to thousands of such stores. I don't care which one called up. Lenger's name is the one that counts; that and his address." "You think that Lenger is involved in the purple deaths?" "I intend to find out. I was satisfied that Grell was the murderer, but that was because there were no links between the clues. This news changes everything, professor. I must call headquarters at once." Five minutes later, Commissioner Weston's limousine pulled away from the front of Murkden's house, followed by two officers in a patrol car. A whining siren cleared traffic for Weston's speedy trip; but the commissioner did not plan to ride with such hubbub as far as Twenty-sixth Street. Over the telephone, Weston had ordered headquarters men to form a silent cordon all about the block where Lenger's apartment house was located. When Weston reached the scene, that cordon would close in, performing the move with stealth. For Commissioner Weston had admitted to himself that he might be wrong about the identity of the purple murderer. For the present, he had put aside the name of Courtney Grell. His whole purpose was to surprise Louis Lenger; to capture the man without a struggle. Unwittingly, the police commissioner had found a scene of action already chosen by The Shadow. Surprises would be due when the law reached its goal. CHAPTER XVII BATTLE BELOW AT the very moment of Weston's start upon his new and active mission, two men were standing in a square-walled windowless room. Stone walls told that this chamber was located underground. The only breaks in the square walls were two doorways, each in a different wall. Both doors were closed. The room was furnished only with chairs and tables, but upon one table stood a large, square-shaped box that looked like a radio receiving set. The front of the blocky object formed a black screen. Upon the wall above was a blackish plate like the one in the entry of Lenger's apartment house. One of the two men was tall and long-faced, his features showed a shrewd grin that revealed yellowed, ugly-shaped teeth. The grin identified him. He was a product of Manhattan's underworld, a one-time racketeer named Bert Thayler. Bert was a crook whose past resembled that of Slook Howdrey; but he was smoother, craftier than the rowdy who had lost the battle in Central Park. The man with Thayler was a thuggish rogue of squatty build. His greasy face carried a brutal leer; his wolfish eyes watched Thayler expectantly. This ruffian was Bert's lieutenant; he was also a character well known in the underworld. He was "Rink" Leed, notorious as an organizer of strong-arm squads. Like Bert, Rink had disappeared from the underworld months ago. "We're all set, Rink," announced Bert, in a purring tone. "All we got to do is pack the telesighter" - he indicated the cabinet on the table - "and yank the special set off the wall." He pointed to the black square above the telesighter. "You hop upstairs and get the finder that's in the entry." "And lam from there?" queried Rink. "Or do you want me back here, Bert?" "Come back here. We'll go out by the route the chief uses. The crew can travel with us." "What about the finder that's at Feasley's?" "The chief will get that." Rink turned toward a doorway. As he did, there was a sharp click from the wall. Both Bert and Rink stared in that direction. A sudden change had come to the black square that was set in the wall. The plate was illuminated. It was grayish instead of black, for the light came through it. On the plate was a picture, projected as upon a screen. The picture showed the little entry of Lenger's apartment house. Bert and Rink watched the screen intently. "NOBODY there," growled Bert. "That's about the tenth time it fooled us, Rink. It's set too sensitive, that's what. Anything going past the front door - like somebody's shadow - is likely to click it. Look - there it goes off again!" The light disappeared as Bert spoke. Again, the black plate showed dully from the wall. Bert turned to Rink. "Better let it stay a couple of minutes," he decided. "Help me pack the telesighter. Then go up and yank the finder." "What about the crew? Want me to call them?" "I'll take care of them, Rink, while you're upstairs." "What're we going to do with the dumb dicks?" "We'll leave them where they are. They don't know what it's all about. There's only one bird in the lot that's got any brains. But he made a dumb duck of himself, too." Rink grinned. He knew the person to whom Bert referred. "Wait until I show you the route we're taking out of here," chuckled Bert. "Then we can pack the telesighter. Look, Rink - this is the way the chief uses." Bert stepped to a blank wall, jammed a thin key deep into a corner crack. There was a muffled click; another crack widened. Rink gaped as a portion of the wall swung away, to reveal a narrow underground passage. Bert pointed along the blackened corridor, looking toward it as he spoke. "It goes clear into the next block," he stated. "Comes up into the old garage where we've got those cars parked. We can make a clean get-away in five minutes, Rink." While Rink was speaking, a motion occurred at one of the doors. Slowly, the barrier came open. Rink heard a squeak of a hinge, turned quickly toward the door. As he did a stocky figure came lunging headlong. Rink tried to pull a gun. He was too late. The attacker was upon him. Bert wheeled about, startled by the sudden fray. He saw a hand grab for the revolver that Rink had pulled halfway from his pocket. The attacker almost gained the weapon, for he had shoved Rink to the wall beside the telesighter and had the rowdy helpless. Rink managed to defeat the grab by the only move that was still open to him. He jolted his shoulders sideways; let go of the gun. It sped from his hand, took a long bounce on the floor and skidded straight for Bert Thayler. The stocky attacker threw Rink aside and started a dive for the lost gun. Bert coolly took command. He clamped his left foot on Rink's revolver; at the same moment, whipped out a .38 of his own, to cover the man who had made the wild attack. The stocky invader stopped short, raised his head and eyed Bert with a scowl. For the first time, the light showed the man's face plainly. The frustrated attacker was Inspector Joe Cardona. "THOUGHT you'd stage a fast one, eh?" sneered Bert. "Well, you didn't get away with it, Cardona. Back up against the wall and keep your dukes high." Cardona obeyed. Bert kicked Rink's gun toward its owner. "Grab your heater, Rink," ordered Bert. "Keep Cardona covered. I want to talk to him." As Rink regained the revolver, Bert concentrated upon Cardona. Bert's tone was vicious. "We figured you for a lug," he told Cardona. "You acted like it, too, right after we grabbed you. We let you get out of that cell we had you in, so you could make a couple of phone calls. We wanted you to make them. "Guess you figured they could be traced back here. They couldn't. Those calls went over a tapped wire; and afterward, we unhooked it. Nobody could trace them after that." Pausing, Bert watched Cardona eye the telesighter and the black block on the wall. He also saw Cardona note the exit to the underground passage. "Take a good gander," jeered Bert. "It's all you can count on, Cardona. We were going to leave you in that cell of yours, like we're doing with those dicks we grabbed before you came along. But since you managed to bust loose from it, we'll give you the works instead. You've got a chance to look at some things you weren't supposed to see. Rink looked expectantly toward Bert. Rink's finger was itching on the trigger of his reclaimed gun. "How about it, Bert?" queried Rink. "Ready for me to drill him? Nobody's going to hear me give it. These walls won't let no noise go through them." Bert shook his head. "I've got a better way, Rink," he declared. "One I was holding in case this happened." Bert looked toward Cardona. "Remember how we handled you when we came here?" Cardona gave no reply. "I'll remind you," chuckled Bert. "We gave you a shot of tear gas, when you were in a place where you couldn't get away from it. So we're putting you back in the same place. But this time the gas tank is filled with the same kind of purple stuff that finished Trumbull Rythe." BERT stepped forward, nudged Cardona with his gun. Joe had only one course; to take the route that Bert indicated. It led to the door that was still closed. With Rink covering Joe, Bert opened the door. The pair moved Cardona into a small room that looked like an entry. In front of them was the door of an elevator shaft. "Call the crew." Bert snapped the order to Rink. "They can stay with me, keeping Cardona covered, while you go up to the front door and yank the finder. As soon as you're back with the elevator, we'll put Cardona aboard. It's going to be swell, having them find this mug all purple." "Not so swell for you, though," said Cardona, suddenly ending his silence. "You want to bump me because I finally found out who you were. But remember - anything you do to me will pin the goods on Louis Lenger. You'll be traced through him." "Lenger can take care of himself," chuckled Bert. "Don't worry about him spilling anything that will make trouble for us. Even you couldn't make Lenger give the low down on the purple death. But you won't be around to try." While Bert spoke, Rink stepped over to a side wall to press a button that would summon the hidden crew. His hand stopped short as a peculiar buzz sounded from above the door of the elevator shaft. A light glimmered from a panel. It showed the figure "1." "Wait a minute, Rink!" snapped Bert. "Somebody's gone on board that elevator. But whoever it is didn't come in through the front door." "He may have," remarked Rink. "We weren't watching the detector panel." "I was listening for it," returned Rink. "I'd have heard it click on and off. Whoever is on that elevator sneaked in through the back door." The number 1 went out. A second later, a new number showed on the panel. It was the figure 4. Bert gave a prompt grunt. "Somebody's going up to the fourth floor," he commented. "It isn't Lenger. He always comes through the front door. Nobody else would be going up there except -" "The Shadow!" Bert nodded as he heard Rink's exclamation. He reached into a niche beside the elevator shaft. He pulled a switch that Cardona saw there. Immediately, the number 4 light went out. Instead, a bulb glimmered showing the letter B. "That will bring him down," grinned Bert. "Like it did you, Cardona. It's a lucky break for you. We'll have to give you bullets, after all. We'd been hoping that The Shadow would show up for the purple gas treatment." CARDONA tightened. He edged toward Bert; all the while, he could hear the rumble of the elevator. It was coming downward. Soon it would strike the basement level. Well did Cardona know the hopelessness of The Shadow's position. Joe had ridden in that same elevator. Bert's pull of the switch had locked the inner door of the car. Solid-walled, with heavy roof, the elevator was a prison from which no occupant could escape in the short time that the descent required. Cardona was ready to make a last thrust, in the hope that he could avert the doom that threatened The Shadow, even if it cost his own life. Bert's gun was aimed toward Joe, but Bert was watching the elevator shaft. The rumble was louder, the car was almost at the bottom. Cardona started his forward spring. It ended instantly. Powerful hands caught his arms from behind, yanked him backward, pinning him helpless. Joe had forgotten Rink. The lieutenant had seen the coming move. He had shoved away his gun to make the grab. Catching Cardona helpless, Rink gave a sideways heave. Joe crashed the wall, jolted the back of his head. He sagged to the floor, half groggy. Rink produced his gun and again covered Cardona. The elevator's rumble ended. Staring hazily, Cardona saw Bert Thayler reach to the top of the little niche and grasp a metal ring. Bert gave a tug; a chain came into view. There was a muffled hiss beyond the elevator door; the surge of the poison gas through tiny holes that lined the walls of the car. Cardona came to hands and knees. His head swirled dizzily. He sagged back, rested limp as he tried to regain his scattered senses. He saw Bert calmly studying the dial of a watch. He heard Bert's remark: "The gas settles inside a minute, Rink. We'll give it two, though -" The two minutes passed like a few hazy seconds to Joe Cardona. He steadied slightly as he saw Bert step to the door of the shaft. The metal barrier clanged open with Bert's pull. Cardona saw the lighted interior of the car. There, on the floor of the elevator, lay the sight that Joe Cardona had hoped he would never view. A black-cloaked figure was sprawled crazily, in a crumpled posture that indicated instant death. One long arm was extended toward the door of the elevator. Its gloved hand was limp; from the unclenched fist had fallen a huge automatic. Beside the shoulder of that same arm was a downward tilted head, its face obscured by folds of a cloak collar. The head itself was hidden, for a black slouch hat had tipped backward, to rest loosely upon head and neck. The interior of the elevator glistened as the walls had shone at Rythe's. Drying drops of condensed vapor caused that shine. They told that the gas had completely filled the elevator. Crooks had gained the chance they wanted. They had loosed the full force of the purple death upon The Shadow. CHAPTER XVIII THE UNDERGROUND WAY BERT THAYLER stepped forward gingerly. He reached the threshold of the elevator, gave a cautious sniff to make sure that the gas had cleared. Satisfied, he stooped and reached downward to pluck the slouch hat from The Shadow's head. Bert paused as he heard Rink approach. He looked over his shoulder, glared angrily at his lieutenant. Bert snapped an order: "Watch Cardona!" "He's groggy, Bert," insisted Rink. "He can't make no trouble." Bert looked toward Cardona, saw that the stocky sleuth was again trying to come to hands and knees. "Call the crew, then," ordered Bert. "As soon as they get here, tell them to plug Cardona. I'll haul The Shadow out of here. The outfit can take a gander at this mug while you're on your trip upstairs. Make it snappy, Rink. Time's short." Rink swung toward the wall, to press the button. Cardona made a wild effort to rise and stop him; then sagged back. On hands and knees Cardona came, face toward the elevator. His chance position enabled him to see what happened there. As Bert swung to reach for The Shadow's hat, his arm went past the extended, black-gloved hand. Momentarily out of Bert's sight, that hand came to life. It dropped; its fingers tightened on the automatic that lay on the floor. Bert yanked away the slouch hat, gave The Shadow's body a roll, so that he could stare at the cloaked fighter's face. What Bert saw must have startled him. Cardona saw a reflected glimmer as Bert suddenly jabbed his revolver straight for the figure on the floor. Cardona also heard the ugly snarl that came from Bert. Simultaneously, Joe saw The Shadow's gloved hand snap upward. Time seemed disjointed to Cardona. He heard a roar from the interior of the elevator. It was the echoing blast of a gun. Almost like a separate occurrence, Cardona saw a flash of flame. To Joe's dazed mind came one distinct impression. That tongue of fire had thrust upward. Therefore it was from The Shadow's gun. The cloaked fighter had beaten Bert Thayler to the shot. Rink Leed heard the blast just as he pressed the button on the wall. Rink swung about with a leer, thinking that Bert had decided to drive a bullet to The Shadow's heart, just for the evil satisfaction that the deed would bring. Rink stopped rigid. He saw Bert's body crumpling, spilling across The Shadow's form. He saw black shoulders rising, he saw a face above them. In that instant, Rink expected to view a purpled countenance. Instead, he saw no trace whatever of The Shadow's actual visage. THE SHADOW, restored to life, looked like some monstrous being. His face was covered with a darkish cloth; from it extended a metallic hose that ran downward to the folds of The Shadow's cloak. Rink saw the glare of eyes that burned through thick, protecting goggles. The object that covered The Shadow's face was a gas mask. The Shadow had recognized the method by which crooks captured unwanted visitors who came to Lenger's. He had seen the elevator as a trap. He had known that only tear gas could have accounted for the capture of Joe Cardona, since it had been followed by the recuperation that Joe had shown through his telephone calls. The Shadow had foreseen that if he entered the trap, he, too, would experience a gas attack. Whether it would be tear gas or a deadlier vapor had not mattered. He had come equipped for either, wearing a gas mask brought from the sanctum. His sprawl upon the floor had been a ruse. He had wanted crooks to think him dead, so as to catch them off guard. Rink's rigidity ended. Hastily, the lieutenant aimed for The Shadow. He was late. Already The Shadow had him covered. One instant more would have spelled death for Rink Leed. Only a misguided intervention saved him. Joe Cardona saw Rink aim. With a heroic effort, Joe sprang for the crook. He grabbed Rink's gun wrist, thrust the crook's hand upward. Though his head was swimming, Joe fought instinctively. He jammed Rink backward; gained a momentary advantage. But with that attack, Cardona came between The Shadow and Rink. Only by a quick halt of his finger did The Shadow hold back his shot. His restraint was timely; the bullet, had it been dispatched, would have clipped Cardona instead of Rink. For a moment, The Shadow eyed the strugglers. Seeing that Cardona had the edge, he changed his tactics. The Shadow made a quick leap to the door on the other side of the elevator passage. The Shadow had heard the pound of footsteps. He knew that Rink's crew was coming, spurred to greater speed because they had heard the boom of The Shadow's gun. Reaching the door The Shadow sprang into the main room just as four hoodlums surged from the other doorway. The crooks saw The Shadow the moment that they arrived. All were swinging ready revolvers; they leveled their weapons toward the gas-masked figure of The Shadow. Hasty aim did not serve them. The Shadow was a move ahead. Not only had he met his foemen on the way; he was ready with two automatics instead of one. He was past his door before the thugs could pick it as their point of aim. He was sidestepping across the large square room, toward the wall where the telesighter rested. THE SHADOW'S automatics stabbed together. Like knife thrusts, their tongued flames cut toward the entering crooks. The foremost arrivals took the opening bullets. They staggered as the others shoved them aside. The second pair fired, swinging their guns in The Shadow's direction. One bullet was high. It thudded the wall above The Shadow's head. The other was wide. The crook who fired it was too hasty in his aim. He fired for a spot from which The Shadow had side-stepped. The slug whizzed past The Shadow's shoulder. Instantly, The Shadow returned the fire. His aim was as accurate as before. One ruffian floundered; the other jounced back against the wall beside his doorway. He snarled as he tried to aim. His arm was unsteady; his gun hand wavered. Another fighter might have stayed to fire more shots at this sagging crook, but The Shadow did not remain. Split seconds still counted. He had business elsewhere. Speedily, The Shadow sprang back to the doorway that led to the elevator. He was just in time to see Cardona lose his grip on Rink Leed's gun. There were shots from the big room, fired by the crooks who sagged there. They were futile; as The Shadow had expected. They did not even find the doorway through which The Shadow had passed. Concerned only with Cardona, The Shadow aimed for Rink, just as the lieutenant twisted and drove his gun hand downward. Rink had unwittingly come into the path of The Shadow's aim. A single shot was all that The Shadow needed. It found Rink's left side. The bullet jolted the crook toward the wall; but it did not stop his gunstroke. The revolver, though it slipped, delivered a glancing blow to Cardona's bobbing head. Both strugglers rolled to the floor. Rink kicked the cement; then quivered and lay motionless. Cardona fell heavily, tried to clamber to hands and knees, but slipped. Again, he made the effort. He clamped his hand upon Rink's dropped revolver, managed to grip it. But he was too dizzy to rise. The Shadow reached the elevator, whipped up his hat that lay beside the body of Bert Thayler. Stepping out, he clanged the door of the elevator, then those of the shaft. He turned to see Cardona trying to rise beside the wall. Joe's fingers slipped as they clawed the stony surface. He was still hanging grimly to the gun that he had claimed from Rink. One-handed in his effort to rise, Cardona slumped. The Shadow aided Cardona to his feet. Groggily, Joe recognized his cloaked rescuer. He let The Shadow guide him to the big room. There, Cardona tried to gasp out words as he pointed to the telesighter and the opening in the wall, that led underground to the distant garage. FROM the side door of the room came a clamor. Imprisoned detectives were hammering the bars of their cells, hoping that they would soon be rescued. For a moment, The Shadow was ready to move to their release. A click from the wall made him stop. Supporting Cardona beside him. The Shadow watched the black panel that showed pictures of all that happened in the entry of Lenger's apartment house. The light appeared; The Shadow viewed the lobby. A man had entered. The Shadow recognized the face of Police Commissioner Weston. Other faces appeared. With Weston were headquarters men. The Shadow saw that one of them was a detective sergeant named Markham, who frequently worked with Joe Cardona. A whispered laugh came from The Shadow's lips. The arrival of these representatives of the law saved him the delay of opening the cells that held the prisoners. Soon, Weston and the others would find this underground lair. They could come here in safety. No longer would the elevator be a trap. The way was clear for The Shadow to travel elsewhere. A quick start was imperative. The Shadow still had work to do. He wanted to reach his next destination without delay. He had the route that offered rapid departure; that tunnel through which Bert, Rink and the others had intended to depart. The Shadow looked at Joe Cardona. He saw that the ace sleuth was steadier. Cardona had shown his nerve to-night; he had risked everything to aid The Shadow. Cardona was entitled to a reward, and there was a way whereby The Shadow could deliver one. With a whispered order to Cardona, The Shadow pushed Joe through the opening in the wall. As Cardona steadied in the darkness of the passage, The Shadow used a flashlight, found a switch and pressed it. The wall swung shut, closing so perfectly that the opening could not be detected. The underground vault was empty of living beings. The Shadow was gone, through the passage beyond, taking Joe Cardona with him. The only evidence of The Shadow's visit were the silent bodies that lay upon the floor. The last sagging thug had toppled with his final hopeless shots. The Shadow had gained full triumph over Bert Thayler, Rink Leed and the four henchmen who served them. Underlings of the purple death were vanquished. The Shadow's next meeting would be with the master murderer himself. CHAPTER XIX THE LAW SEES COMMISSIONER WESTON, standing in the entry of the apartment house, was completely ignorant of the fact that his presence had been observed from a lair below. Like every one else who had visited this entry - with the exception of The Shadow - the black finder plate on the wall was meaningless. Weston's sole purpose was to invade these premises and trap Louis Lenger in his fourth-floor apartment. With that plan in mind, he tried the inner door and found it unlocked. Leading the way through the first floor hall, Weston found the elevator shaft. Instead of sending men up on the elevator, Weston ordered them to use the stairway, so that they could inspect the intervening floors. As soon as a small squad had started, he ordered Markham to remain with him and keep watch on the front door. Weston had already posted men in front of the apartment house and in back. The commissioner was standing by the elevator shaft when he saw some one come into the entry. Thanks to a glass panel in the inner doorway, Weston observed a pair of shoulders; above them a rugged face topped by shaggy hair and derby hat. Suspecting that the arrival might be Lenger, Weston stepped out of sight beyond the elevator. Markham promptly joined him. A few moments later, the man came in from the entry. He approached the elevator; turned to open the door. Looking past him, Weston saw a face at the entry door. He caught a signal of an upraised hand. It was one of the outside detectives. He had seen the rugged-faced man open a mail box in the entry. The dick had thus learned that the arrival was Louis Lenger. The signal transmitted the news to Weston. The commissioner stepped into view; Markham was beside him with ready revolver. Lenger turned as they approached; his eyes glared with suspicion. His fists tightened as he saw Markham's revolver; then relaxed as he saw the detective sergeant display a badge. "What is the trouble?" inquired Lenger. "I was rather startled, gentlemen, before I realized that you were police." "I am the police commissioner," informed Weston. "I have come here to interview you, Mr. Lenger." Surprise showed on Lenger's face. Weston bluntly added the statement: "I have some questions to ask you regarding Courtney Grell." "Courtney Grell?" questioned Lenger. Then, in a reminiscent tone: "Ah, yes. I remember him. He was here last night; a chess enthusiast like myself." "How late was Grell here?" "I disremember. We went out together; stopped in a little restaurant to chat while we had a cup of coffee. Tell me, commissioner, is Grell wanted by the law?" Weston stared; then demanded: "Don't you read the newspapers, Mr. Lenger?" "Only the chess columns. Why?" "Then I am to suppose that you are ignorant of the fact that Grell died last night?" LENGER looked dumfounded. "Grell died a victim of the purple death," stated Weston, eyeing Lenger closely as he spoke. "Suppose we go up to your apartment, Mr. Lenger. No, not by the elevator" - he stopped Lenger as the heavy man reached to press the button. "The stairway would be better." Weston chose the stairway knowing that Markham would be joined by detectives during the ascent. Moreover, the commissioner kept up a running fire of remarks as they went up the stairs. "We thought that Grell was a suicide," he told Lenger, "but we need more facts to be sure. It was odd, Grell dying from the purple death. Of course, you have read about the purple death?" "Yes, I did," returned Lenger. "But I am not interested in such matters." "You live here alone?" "Yes. I am the owner of this building." They reached the fourth floor, to find two detectives in Lenger's apartment. The dicks had already begun a search, losing no time when they found that Lenger was absent. One detective gave the immediate announcement: "We've found plenty, commissioner." Weston motioned Lenger to a chair; told Markham to watch the suspect. He began to examine the evidence that the detectives had uncovered. Their finds popped thick and fast. The detectives produced the box that had contained a fountain pen of the type found on the scene of one murder. They showed Weston the frayed shirt with the missing button. Weston, himself, spied the bottle of purple ink. A detective produced the box of chess clippings; his teammate displayed blank memo pads. Among the chess clippings, Weston discovered the blue pencil. Then came the items that concerned dead victims. First, the blue-marked page from the university catalog, containing the name of Ardess, the murdered instructor. Next, the pawn ticket from Gringew's shop. After that, Tabor's business card; the page from "Who's Who" that displayed Rythe's biography. The final touch came when Weston opened the folded list; read the typed names of victims, ending with Horace Selbart. One of the detectives shoved a sheet of paper into Lenger's old typewriter; typed a few lines and compared them with the list. It was obvious that the names had been typed on Lenger's machine. Weston turned coldly to Lenger; handed the man a blue pencil and a sheet of paper, with the request that he write a few words and sign them with the letter "L". Lenger looked puzzled; then nodded and complied. The commissioner examined the writing. It corresponded with the memo found at Rythe's. "I was wrong about Grell," declared Weston, in a harsh tone. "He was not the murderer who perpetrated the purple deaths." LENGER stroked his stubbly chin. "I thought that chess was a game for a keen mind, commissioner," he asserted. "I learn, at last, that it is no more than a childish pursuit. You come here; you pick out odds and ends from among my papers. From them, you form the remarkable conclusion that Courtney Grell, whom I met but once, is not a murderer. I would not be astonished if, from this same evidence, you discovered who actually is the murderer." "I have done that," retorted Weston. "Your bluff is finished, Lenger. You are under arrest for the perpetration of those crimes." "I?" exclaimed Lenger. He stared; then gave a short laugh. "This is preposterous, commissioner. I do not even know who was murdered." "Perhaps," returned Weston, "you will try to tell me that you never saw these before." He handed Lenger the catalog page that bore the name of Ardess; then the pawnbroker's ticket; the card that bore Tabor's name; finally, the page from "Who's Who" that referred to Rythe. Lenger studied the exhibits. He passed back all of them except Tabor's business card. "I never saw any of those," he insisted. "How they came here is a mystery to me. The business card, though, was among my own papers; but I never met Frederick Tabor personally." "Then how do you happen to have his card?" "I told you that I owned this apartment house," explained Lenger, calmly. "Tabor was the architect who drew up the plans for its reconstruction. All the details, however, were handled by the contractor." Weston studied Lenger intently. The commissioner realized that he needed stronger tactics to jolt Lenger's calmness. Weston produced an envelope from his pocket. "Three nights ago," he told Lenger, "Frederick Tabor was found dead in his studio. This chess clipping" - Weston exhibited the item - "was found on the premises." Lenger eyed the clipping and nodded. "An interesting problem, that one," he remarked. "But the answer given is not the best one. I remember that Grell and I discussed that very problem -" "Two nights ago," broke in Weston, "Trumbull Rythe was murdered in his home. This blue-penciled memo, signed with the letter 'L,' was found there." "That is curious!" exclaimed Lenger. "That looks like a memo that I left in my mail box one day when I expected a visitor. Some one must have taken it -" "Last night," interrupted Weston, curtly, "Horace Selbart was murdered in his penthouse. This blue pencil was found with his body." "It looks like one of my pencils," admitted Lenger. "I have a lot of them here in the apartment. I mislay them often. Do you suppose that some one has -" "I suppose that you are the murderer who slew those three men. Let me add another statement, Lenger. Tabor, Rythe and Selbart were murdered at half past eight, on three successive nights. Where were you at that particular hour, on each of the last three nights?" Lenger arose from his chair. "That is easily answered, commissioner," he stated in a pleased tone. "Every night at eight-thirty, I am with my friend Howard Feasley. We play chess until nine. Feasley lives on the outskirts of Greenwich Village. I can give you his address; you can go there and see him." "HE'LL come to headquarters," retorted Weston. "That's where I am taking you, Lenger." Grabbing the suspect's arm, Weston shoved Lenger out into the hallway and headed him toward the elevator. On the way, Lenger began a protest. "You can not call Feasley to headquarters," he insisted. "The man is still an invalid. He can not be taken outdoors in this chill weather." Weston pressed the button for the elevator. "I shall attend to Feasley," he said, coldly. "We shall check whatever alibi he gives you, Lenger." The accused man smiled. Apparently, Lenger was willing to bank entirely upon Feasley's statements. Silence followed, except for the ascending rumble of the elevator. Lights appeared beyond the frosted glass of the shaft door. Weston opened the door; he stepped back with a startled exclamation. Lenger gulped an odd cry. On the floor of the elevator lay the body of Bert Thayler. Markham stepped aboard; lifted the dead crook's head and turned to the commissioner. "Bert Thayler," informed Markham. "A bad egg. As bad as Slook Howdrey. He's probably the guy who took over Slook's job, commissioner." "Working for the purple murderer!" exclaimed Weston. "But where could the body have come from, Markham?" "From the basement, maybe," suggested Markham, unable to think of a better answer. "If we went down there, commissioner -" "Remove the body. We are going to the basement." Soon, the elevator descended minus Bert's corpse. The passengers were Weston and Lenger, accompanied by Markham and a pair of detectives. They reached the basement. The moment that Markham opened the door, they saw Rink Leed's body. Markham identified Thayler's lieutenant. Weston heard shouts as he stepped to the door of the big room. Bringing Lenger with them, the investigators found the bodies of the dead thugs. They saw the door to the side passage; took it and discovered a row of small cells. Behind the bars were the missing detectives. Weston snapped queries while Markham and others were pounding the locks with revolver butts. Every prisoner had the same story. Each had received a telephone call, telling him to call on a man named Lenger. Each had come to the same apartment house, had been gassed in the elevator. Weston inquired for Cardona. The prisoners told him that Joe had broken free to-night; that there had been gunfire, but Cardona had not returned. Weston had just finished this inquiry when the final lock was smashed. The prisoners crowded out into the corridor. With eight men at his heels, Weston marched Lenger out into the big room. The suspect was handcuffed and helpless; he seemed totally bewildered by the new discoveries. Weston decided on another quiz. "THE facts are plain, Lenger," snapped the commissioner. "You arranged this lair. These crooks served you, just as Slook Howdrey and his ruffians did. You can gain nothing by useless bluff. You are the only man who could have engineered the purple deaths." Weston waited for Lenger to reply. Tense silence was broken by a sudden click from the wall. Weston looked in that direction. The black panel had lighted. It showed the entry. In the picture, Weston saw the faces of two outside detectives. "A television device!" exclaimed Weston. "It must be controlled by a photoelectric cell. The moment any one enters the building, the scene is registered down here. That is how the crooks knew when to use the elevator as a trap!" The panel darkened. The detectives had stepped from the entry. Weston eyed the big cabinet that Bert had termed the "telesighter." Approaching it, Weston noted that the device had a special regulator that was set at a number. He saw a switch. He pressed it. Immediately there was a buzz from the cabinet. The front became a grayish screen; its scene was indistinct at first. In low tone, Weston spoke. "A television device," declared the commissioner. "Let us hope that it is tuned in to some given place. Perhaps from this we can gain new clues." The screen was clearing; a scene began to appear. With it were sounds. The watchers could hear a wheezy cough just as the picture made itself plain. They were looking into a room where a man sat at a chess board. Frail and wan-faced, the man was coughing. He recovered from his spell and reached for one of the chess pieces. The background of the room was plain. At one side was a closed door; at the far end of the room, the viewers saw heavy curtains. Louis Lenger gave an exclamation that betokened recognition. He knew the identity of that frail man who was garbed in dressing gown. Lenger craned closer to the telesighter screen. "Howard Feasley!" he exclaimed. "The man I told you about, commissioner. He is working on a chess problem that we discussed after our game to-night. He must have forgotten that it is after nine o'clock. Otherwise he would be in bed." Weston motioned for silence. Lenger quieted, stood as tense as the detectives who surrounded him. Weston had spotted a change in the scene. The door at the side of Feasley's room was opening. Those who watched could hear the groan of a hinge; but Feasley, actually in that pictured room, did not apparently notice it. He was too deeply engrossed in his chess problem. Something about the scene presaged a coming menace. The men who watched the television screen were helpless to intervene. They could do no more than gaze in rigid horror at the changing picture that revealed those distant events. Commissioner Weston somehow sensed the significance of the slowly opening door. From his lips came an involuntary statement: "The purple murderer!" CHAPTER XX THE LAST DEATH HOWARD FEASLEY shifted back in his chair. His wan face showed a satisfied smile. He had completed the problem upon which he worked. Casually, the invalid glanced toward a mantel. He saw a clock and noted that it was after half past nine. He started to rise from his chair, his eyes still on the clock. He stopped; his lips twitched. In the mirror behind the clock, Feasley saw the reflection of the opening door. From his position, he could see a face beyond it; one that was not visible across the television apparatus, because the door intervened. Feasley spun about; clutched the arms of his chair. A man stepped into the room and closed the door behind him. Calmly, the intruder stepped toward the quaking invalid. Though Feasley had never seen his visitor before, he knew that the man had come with evil intent. The intruder's expression showed it. The face that Feasley saw was a gloating one; the approach that the intruder used was an insidious creep. There were others who saw that face and recognized it, despite the fact that its usually friendly expression had changed to a vicious gloat. The man who had entered Feasley's isolated abode was Professor Kinsley Murkden. Feasley sank into his chair as the professor neared him. Murkden reached the side of the chessboard and eyed Feasley as a snake studies a hapless bird. Stupefied, the chess player blinked. He recognized that Murkden intended ill; but he could not understand why. From a coat pocket, Murkden produced an object that glistened. Feasley saw it, recognized that it was a hypodermic needle. The invalid quivered, tried to twist away from his chair. Murkden shot his free hand forward, thrust Feasley downward and held him helpless. "Death will be prompt," declared Murkden, in a dry, insidious tone. "Unfortunately, Feasley, I am forced to end your life." Feasley found words. "Why - why kill me?" he blurted. "Whoever you are - I have never harmed you." "Quite true," agreed Murkden, his voice carrying an ugly sneer. "I owe you an apology for my action. Therefore, I shall give one. Perhaps you have heard of the purple deaths -" Murkden paused as Feasley's face showed white with terror. He saw his victim make an effort to nod. "I devised the purple death," announced Murkden, proudly. "I reserved it for some important use. Not long ago, I learned of a remarkable invention; a television apparatus that can be added to an ordinary set. It is an invention, I might state, that is worth millions. Its transmission and reception are of such high quality that messages, when sent, can be heard only in a limited area. "With this device, it will be possible to revolutionize the entire broadcasting systems of the world; to control, through international patents, companies that will produce greater wealth than any enterprise in modern history. I have tested the device from this very room." Murkden chuckled as he paused to motion toward the wall. "That black plate that covers your unused wall bracket is both a finder and a transmitter that picks up all that occurs here." FEASLEY was staring; his eyes had temporarily lost their horror and were displaying interest. Murkden's sudden switch from the subject of death had given the invalid hope that the professor might be humored. "An obscure mechanic invented the device," explained Murkden. "It was improved by a college instructor. A radio announcer was called in secretly to aid in its tests. A promoter learned of it, offered to sell the idea. He tried to raise money from a pawnbroker, but failed." Feasley, who read the newspapers, realized that Murkden had explained the reason for the first five purple deaths. They had eliminated all men concerned with the development of the television device. "They finally went to a man named Horace Selbart," continued Murkden. "He financed the invention, upon terms that gave him control of its future. At about that time, I learned of it. I proceeded to use the purple death to eliminate all those whom I have named. "I needed a dupe; one upon whom the murders could be pinned. I chose Louis Lenger, a friend of yours, because it was an easy matter to turn the evidence against him. Chiefly because Lenger had a set policy of being absent from his apartment every night between the hours of seven and nine." "When he came here," blurted Feasley. "That is why you chose Louis Lenger -" "Yes. It was a simple matter to visit his apartment soon after seven o'clock. There I acquired bits of evidence to incriminate him. I also planted items that would serve against him. Lenger's place was in such disarray that I knew he would never find the objects that I had placed." Murkden paused. Feasley's breath came tensely. Murkden heard its sighing tone and his eyes gleamed wickedly. The scheming professor had not only proven that his usual mild manner was a pose; he had also demonstrated that his supposed deafness was a pretence. "I planned this long ago," chuckled the murderer. "I had picked Lenger for my future dupe. I intercepted rough plans that Lenger had made for the reconstruction of two old houses into an apartment building. I added instructions of my own. As a result, the architect added a stronghold in the basement. That architect was Frederick Tabor. I killed him, took the old plans from his files. That murder, too, will be pinned on Louis Lenger. "Looking to the future, I could see but one man who might block my great plans for international control of television. That man was Trumbull Rythe, the financier. Among his many holdings were options on certain forms of radio equipment that are at present regarded as unimportant; but which will be vital to the production of the television apparatus that I required. By eliminating Rythe, I removed the one obstacle that night have blocked my path to commercial supremacy." With that statement, Murkden changed his manner. He had lessened his evil glare. Viciously, he resumed it. His left hand settled clawlike upon Feasley's shoulder. His right hand approached with the deadly hypodermic. Feasley was too paralyzed to writhe. "My apology is ended," sneered Murkden. "It is time that you should die." "BUT why?" gasped Feasley. "I have not tried to block your schemes." "You are Lenger's alibi," croaked Murkden. "The law is ready to class him as a homicidal maniac. When you are found a victim of the purple death, Lenger's last hope will be gone. Particularly" - Murkden's tone was gloating - "because the law believes that every victim died at half past eight. "To-night, my henchmen watched - as they have always watched - to see when Lenger left here. To-night, they saw him leave. They sent a tip-off to the police. I answered the call myself, in Commissioner Weston's presence. By this time, my men have left their stronghold. Lenger is in the hands of the law. The police will come here; that plate on the wall will be gone. But they will find you dead and purple -" Murkden halted. Feasley's wild, hopeless eyes had gained a sudden light. They were looking past the hand that held the hypodermic; beyond Murkden's shoulder to the curtains at the rear of the room. Sharpness came to Murkden's gaze. Instantly, the murderous professor spun about. Straight before him, Murkden saw The Shadow. Curtains had parted to admit the black-clad avenger. With leveled automatic, The Shadow approached. Murkden backed away from Feasley. Though his livid lips still showed viciousness, Murkden knew that he was trapped. With long stride, The Shadow stepped between Murkden and the door. Burning eyes fixed themselves upon the half-crouched murderer. Murkden glared back. His fists were clenched; the right one still held the hypodermic. For a moment, Murkden seemed ready for a spring; then he recognized the futility of such a move. The looming muzzle of The Shadow's .45 was too powerful a threat. "You forgot the mention of one victim." The Shadow's tone came in sinister syllables. "I refer, Murkden, to the man that you were forced to kill. That man was Courtney Grell." Murkden scowled, but made no response. "You wanted clues to reach the law," continued The Shadow, "so that Lenger could be incriminated. But your methods required that those clues be held back until you had completed your chain of murder. That was why you trapped the law's investigators. "Grell investigated also; but he was not trapped, even though he visited Lenger. That was proof that Lenger was not the purple murderer. I looked for an answer to the riddle of Grell's death. I found it. Grell was the only man who visited Lenger and found him at home. Grell entered the elevator trap; but Lenger was with him. Since Lenger was to remain at large, an unsuspecting dupe, your henchmen could not spring the trap on Grell. "Instead, they let him go, knowing that he would return to your residence, either to inform the commissioner of what he had learned or to continue with a bluff that would suit his own plans. Commissioner Weston was gone when Grell arrived, but you talked with Grell and lulled him into thinking that Weston was not angry. Meanwhile, you had prepared the poisoned chewing gum. One of your servants planted it in Grell's overcoat pocket, while Grell was with you." A SNARL formed on Murkden's lips, plain proof that The Shadow had been right in his reconstruction of events. Realizing that his expression was a betrayal, Murkden stiffened. Forgetting that he was trapped in an attempted murder, the professor suddenly reverted to the past. "You have no proof," he grated. "No one will believe your statements. My tests - certified by experts - proved that the purple death was delivered each night at half past eight. I can bring dozens of witnesses to prove that I was always in my lecture room at that precise time." "Your proof will be useless," asserted The Shadow. "Your scheme was clever. It began when you hired Slook Howdrey to intimidate Commissioner Weston, with the demand that no tests be made. You hired Slook without revealing your identity. Facts seemed to show that some hidden killer regarded your blood tests as a menace to his career of crime. "Established as the one man who could solve the riddle of the purple death, you prepared your Compound 'F' and made it almost identical with the poison. The tests that you made were genuine. They were thoroughly checked by experts and accepted. But no one thought to examine the guinea pigs that you used. "I performed the tests with other specimens. I learned that the purple death had struck at half past nine, a time when you were free to deliver it in person. The guinea pigs that I used were ordinary ones. Your guinea pigs were inoculated; you tinged their blood beforehand with a small dose of the purple poison. When you killed them with a full injection, their first blood changes were slow, and did not reach the correct ratio for a full hour. Thus your tests with guinea pigs gave false proof that the human victims had died at half past eight instead of half past nine." Murkden's glare was gone. The Shadow had revealed the facts behind the murderer's cunning game. For a few moments. Murkden cringed. His expression showed no vestige of its former confidence. Then came a sharp glint from evil eyes; simultaneously, a warning gulp from Feasley, who had been an awed and silent spectator during The Shadow's denouncement. The Shadow needed neither warning. A groan of a door hinge told him that Murkden and Feasley had seen something occur behind him. The Shadow was spinning about as the door swung violently inward. Gun ready, he sprang straight for the doorway to meet a massed surge of three attackers. The men were Murkden's servants. The professor had brought them along to stay on watch outside. They - like Murkden - had arrived after The Shadow had already entered to take his post behind Feasley's curtains. The blast of The Shadow's automatic dropped the first attacker. The second, springing past the cloaked fighter, turned to aim. The Shadow sledged him unconscious with a hard swing of the automatic. With his stroke, The Shadow made a complete spin, came upon the third henchman before the startled man could fire. Wildly, the last of the trio grabbed for The Shadow's gun arm. The Shadow's hand twisted free poised for a downward stroke that would end the conflict. His back was toward Murkden. The murderer saw the opportunity he wanted. Murkden had forgotten Feasley and with good reason. All that the invalid could do was shriek a warning as Murkden bounded toward The Shadow. Down came The Shadow's gun arm. Murkden's last servant fell. Simultaneously, Murkden swung his hand above The Shadow's back. The hypodermic glistened from the claw that clutched it. One second more, Murkden could have driven the needle home, to change The Shadow's triumph into doom. The gloating murderer was sure that he could claim The Shadow as the final victim of the purple death. As Murkden's poised hand moved, the report of a revolver echoed through the room. The shot came from the curtains that had been The Shadow's hiding place. A steady gun had aimed for Murkden. The bullet found the murderer's body. As Murkden wavered, smoke curled from the curtains; then the draperies parted. A stocky marksman sprang into view. The sharpshooter was Joe Cardona. The Shadow had brought the missing inspector with him. From the moment that The Shadow had confronted Murkden, Cardona had been holding a bead upon the murderous professor. Joe had hoped to capture the killer alive. The chance arrival of Murkden's reserves had made it imperative for Cardona to fire. One bullet, though well aimed, was not enough to finish Murkden. The professor wavered; then recuperated. His lips snarled as his right hand tightened. The Shadow wheeled about to see Cardona stopping for new aim. Before the ace inspector could fire, Murkden jabbed his hypodermic for The Shadow's turning shoulder. A gloved fist, quick as a trip hammer, came up to clutch Murkden's driving wrist. The thrust stopped short, the needle point pricking the folds of The Shadow's cloak. With a powerful twist, The Shadow turned back Murkden's hand, pointing the needle in the opposite direction. For a moment, Murkden was rigid. Suddenly his strength faded. He toppled forward, a dead weight, succumbing to the mortal wound caused by Cardona's bullet. The full pressure of the killer's chest struck squarely on the back-turned needle. The long point pierced straight to Murkden's heart. The Shadow released the crumpling body. Murkden folded on the floor, face upward. Cardona, staring downward, saw a weird change come upon the murderer's frozen countenance. A crimson flush covered Murkden's features. The tinge darkened; grew to a terrible purple that brought a gruesome swelling to the dead man's face, a purplish bulge to evil eyes that were staring fixed in death. DISTANT observers saw the sight. Weston, Lenger and those with them were staring at the telesighter screen. They had heard every word that had passed at Feasley's. They had learned the full truth of Kinsley Murkden's crimes. They viewed the aftermath. Murkden prone and lifeless, his purple face showing dark upon the screen. They saw Cardona gazing at the dead murderer; Feasley, half up from his chair, gasping in relief at sight of the doom that he had missed. Beyond that tableau was The Shadow. The cloaked victor turned, stepped slowly to the far curtains and paused there for a final view. Gloved hands spread the curtains; The Shadow took a backward step between. The curtains dropped. The Shadow was gone. There was a pause as the curtains ceased their rustle. Then, from that hidden spot, came a final token; a sound that quivered through the room where Cardona and Feasley stood and carried its chilling echoes through the ether to those who watched and listened at the telesighter. That sound was a laugh that rose to weird crescendo, then faded into nothingness, yet seemed to echo in the brains of those who heard it. That peal of solemn mirth betokened The Shadow's triumph. It marked the black-clad victor's departure. There were ears that that weird tone could not reach; ears that had gained a deafness more permanent than they had once pretended. Those were the ears of Professor Kinsley Murkden. That master murderer would never again move to crime. Purple death had ended its reign forever. The Shadow's hand had turned its final thrust. The last dose of the purple poison had found its proper lodgement in the death-stilled form of the murderer who had created it. But The Shadow's hand would be thrust forward again, in the future, grimly clutching for the lead that would bring together "The Seven Drops of Blood." Priceless rubies from the storehouse of an Oriental potentate, then the prize piece of a wealthy gem collector - The Shadow battles the master thief who separates the seven glittering stones, and traces them one by one in a relentless struggle against the pick of the underworld. THE END