Twenty minutes later, having satisfied himself that the immediate neighborhood was free of passers-by for the moment, and that he had not been observed, he tried the street door of the tenement that had been the subject of Whitie Jack’s earlier investigations. The door was unlocked, and he stepped silently into the vestibule, and closed the door softly behind him.

He stood for a moment listening, and taking critical note of his surroundings. A single incandescent burning here in the lower hall supplied ample illumination. The stairs were directly in front of him, and on the right of the hallway. There was a closed door, also on the right and just at the foot of the stairs, and from behind this there came the murmur of voices. There was no other sound.

He moved quietly forward, mounted the stairs, gained the landing, and, with more caution now, turned back along the hall, making for the door on the right—Peters’ door, according to Whitie Jack—that, if in the same relative location as the one below, would be at the foot of the next flight of stairs. A faint light came up through the stair well, but the end of the hall itself beyond the second flight of stairs was in blackness. He nodded grimly in satisfaction. He would not need any light to find Peters’ door!

His lips pressed hard together. He had reached the door now, and now he crouched against it, his ear to the panel. He listened intently. A sudden doubt came and tormented him and obsessed him. What, if by any chance Peters had someone with him! A bead of moisture oozed out on his forehead, and he brushed it hurriedly away. He was not so callous now! Behind that door lay, literally, life and death; behind that door, if it proved necessary, he meant to take a man’s life, a miserable life, it was true, a murderer’s life, a life that had no claim to mercy, but still a man’s life. Had he ever laid claim to being callous? But that did not mean that his resolution was being undermined. The issue to-night was clearly defined, ultimate, final, and he had accepted that issue, and he would see it through. His lips relaxed a little in a smile of self-mockery. Well, suppose Peters were not alone he, Billy Kane, had only to wait until the visitor conjured up by his doubts had gone.

He steadied himself with a mental effort. His nerves were getting a little too high strung. To begin with, there wasn’t anybody in there with Peters. He would have heard voices if there had been, and he had heard none. He glanced around him now, but the act was wholly one of exaggerated caution. Here at the end of the hall he could see nothing. Opposite him was probably the door of the other apartment on this floor that Whitie Jack had said was unoccupied. There was no fear of interruption. He took his automatic from his pocket, tried the door cautiously, and finding it locked, knocked softly with his knuckles on the panel.

There was no response. He knocked again, a little louder, more insistently. There was still no response. Billy Kane was gnawing at his under lip now. Not only had Peters no visitor, but even Peters himself was not there! Out of the darkness it seemed as though a horde of mocking devils were suddenly jeering at him in unholy glee. He had somehow been very sure that everything to-night would go as he had planned, and, instead, there had been nothing so far but stark futility.

But the night was not ended yet! He thrust the automatic abruptly back into his pocket. There was still time for Peters to come. It was only a little after nine. And Peters would have a visitor after all—a visitor waiting there inside that room for him!

Billy Kane drew Whitie Jack’s bunch of skeleton keys from his pocket, and, crouching now low down in front of the door, inserted one of the keys in the lock. It would not work. He tried another with the same result. He was not an adept at lock-picking as yet! He grinned without mirth at the mental reservation—and suddenly drew back from the door, retreating into the deeper blackness at the end of the hall. Here was Peters now, and Peters would have much less trouble in opening the door!

Footsteps were ascending the stairs. A figure, in the murky light from the stair well, gained the landing, and came forward along the hall. Billy Kane’s sudden smile held little of humor. It was not Peters. It was Whitie Jack’s tenant of the third floor, Savnak, the old violin player, hugging his violin case under his arm, and as he came into the shadows, feeling out with his other hand for the banisters of the second flight of stairs. Fifteen feet away, flattened against the wall, himself secure from observation, in the darkness, Billy Kane, in a sort of grim philosophical resignation, watched what was now little more than a shadowy outline, as the other went on up the stairs to the third floor.

A door above slammed shut. Billy Kane returned to Peters’ door. Again he tried a key, and still another, until, with a low-breathed ejaculation of satisfaction, he finally unlocked the door. He exchanged the keys for his automatic once more; and once more his hand on the doorknob, he held tense and motionless, listening. From below there came again the sound of footsteps on the stairs. It was Peters at last, probably; but, if it was Peters, Peters was not alone. The footsteps of two men were on the stairs.

Futility again! The door was unlocked, but it availed him nothing at all now. He had meant to go in and wait for Peters, but it would be a fool play from any angle to go in there now if Peters had anybody with him. Nor was there time to lock the door again. He had returned the bunch of keys to his pocket, and it would take a moment to sort out the right one, and there was not that moment to spare. The footsteps were already on the landing. Billy Kane drew back once more silently and swiftly to the front of the hall. He was tight-lipped now. It seemed as though every turn of the luck had gone against him. Peters was certain to notice that the door was unlocked. What effect would that have on Peters? What would the man do, and——

Billy Kane was staring down the hall in a numbed, dazed way. Two men had come into the radius of light from the stair well, and were moving quickly along the hall in his direction. He brushed his hand across his eyes. That little horde of devils were at their jeers of unholy mirth again. Peters! There was no such man as Peters! Peters was a myth! The whole cursed night was a series of damnable hallucinations. This wasn’t Peters—it was Red Vallon, and Birdie Rose.

Out of the darkness he watched them, his mind fogged. What were they doing here? Why had they become suddenly so quiet and stealthy as they went up that second flight of stairs—where Savnak had gone! Savnak—Vetter—the diamonds—Red Vallon! He remembered the tribute paid to the Mole’s cleverness, a tribute that, in his estimation as an eyewitness to the theft, had come far from being borne out in practice. Was there something that he had not seen, something behind that bald, crude scene which he had witnessed? His brain was stumbling on, groping, striving for understanding. He remembered the code message—the Mole was to divert suspicion to someone else. Had the Mole in some way outwitted Red Vallon? Birdie Rose and Red Vallon obviously believed that the old violinist had the diamonds—there was no other possible explanation to account for their presence here hard on Savnak’s trail. And if that were so, it would go hard with Savnak, very hard, indeed, when, believing Savnak was lying, Red Vallon failed to secure the stones. Red Vallon was not a man to trifle with; Red Vallon was perhaps the most dangerous and unscrupulous gangster in New York, and——

Billy Kane was creeping forward, and mounting the stairs step by step with infinite caution. They had disappeared now into Savnak’s room, presumably.

He had no choice, had he? The man-handling they would give Savnak would be little short of murder. Murder! His lips tightened. There was to have been murder in that room below there—wasn’t there? But that was different—one man was guilty, the other innocent. Much as it meant to him to settle with Peters, he had no choice but to let that go to-night now, if necessary—to let it go, if necessary, until to-morrow, or until he could formulate some other plan, for it was not likely that he could frustrate Red Vallon now, and still be left quietly to return to a reckoning with Peters.

His fingers closed in a sudden spasmodic clutch over the stock of his automatic. He had passed Peters’ door, and left it unlocked, and Peters might come in the meantime. Well, it didn’t matter now! His own luck was out! The night had done nothing but toss him hither and thither like a shuttlecock in mockery and sport. And at the last fate had played him this most scurvy trick of all. He could not stand aside and see an innocent man left to the mercy of a devil like Red Vallon, and so, instead of playing Billy Kane to Peters, he was playing the man in the mask to Red Vallon and Birdie Rose! And that jeering horde of imps out of the darkness were shrieking in his ears again!

He slid his mask over his face. He had reached the door over Peters’ flat, which Whitie Jack had described as Savnak’s. Red Vallon had failed to close it tightly behind him—perhaps unwilling to risk the chance of any additional sound. It was slightly ajar. A dull glow of light, as though from an inner room, seeped through the aperture. Came a sharp, startled exclamation, and then Red Vallon’s voice, snarling viciously:

“Come on! Come across! And come—quick!”

Billy Kane pushed the door open inch by inch, and suddenly slipped into the room. He was quite safe, providing he made no noise that would betray his presence. Across from him, at an angle that kept him out of the line of light, was the open door of what was obviously the front room of the apartment. Savnak had evidently been flung violently down into a chair; Birdie Rose’s fingers were crooked, claw-like, within an inch of the violinist’s throat; and Red Vallon, leaning on a table in front of the two, was leering at Savnak in ugly menace. Savnak was speaking, low and earnestly, but Billy Kane could not catch the man’s words. Red Vallon interrupted the other with scant ceremony.

“Can that!” he snarled. “It don’t go! That stagehand of yours ain’t got the goods—you got ’em. We’re wise to your game. We know you, Birdie and me, and you know we know it. How long you been cultivating the old Dutchman, and waiting for something worth while like to-night to break loose? Pinochle and a violin! Pretty nifty, that violin stunt! It helped a lot—we got in the same as that boob of yours did—while you was making enough noise fiddling to let an army in without being heard. Sure, you got a tricky nut on your shoulders, all right! It’s too bad, though, you don’t know enough not to stack up against a better crowd! And the guy turned out the gas to help him in his get-away, did he? Yes, he did—like hell! That’s where he slipped you the sparklers, old bucko! Well, we’ve got your number, ain’t we? We hung around after that to give you a chance to finish out the play. We’re with you there! Nothing suits us better than to have the police chasing some guy they don’t know, and that ain’t got the white ones anyhow! Come on now, come across!”

Billy Kane, like a man bewildered, mentally stunned, stood there motionless. A singsong refrain repeated itself crazily over and over again in his brain: “Savnak was the Mole! Savnak was the Mole!” He lifted his hand and swept it across his eyes. Savnak’s face in there in that room was working in a sort of livid fury. Yes, of course—Savnak was the Mole. It was quite clear now, quite plain—and the Mole was not lacking quite so much after all in craft and cunning! So Red Vallon had been in Vetter’s, too, had he? There came a sudden, grim set to Billy Kane’s lips. Well, at least, the diamonds were here now!

Savnak was speaking again.

“Who put you wise to this?” he demanded sullenly.

“I dunno!” said the gangster indifferently. “I got orders, that’s all. Mabbe some of our crowd piped you off making your play with Dutchy during the last month, and figured two and two made twenty-three—for you; or mabbe one of your own bunch whispered out loud. I dunno! Are you coming across without getting hurt, or aren’t you?”

Billy Kane was moving softly toward the inner door. Savnak had apparently regained his composure. He looked from one to another of his captors, and forced a smile.

“Look here,” he said ingratiatingly, “we’re all in this. Suppose we play fair. I’m willing to split.”

“D’ye hear that, Birdie?” jeered Red Vallon, with a nasty laugh. “He wants a split! Well, give him one—mabbe it’ll help him to get a move on! Twist his pipes a little more—that’s the sort of split he won’t argue over!”

Birdie Rose’s two hands closed with a quick, ugly jerk on Savnak’s throat. There was a gurgling cry.

“Wait!” Savnak choked out. “Wait! It’s—it’s all right, boys.” He rubbed his throat, as Birdie Rose released him. “I know when I’m beaten.” He shrugged his shoulders in a sort of philosophically fatalistic way, and, reaching into his inside coat pocket, threw Vetter’s chamois pocketbook down on the table.

“That’s the stuff!” grunted Red Vallon maliciously. “But seeing it’s you, we’ll just take a look at it to make sure you’re honest!” He picked up the pocketbook, opened it, nodded and chuckled over the gleaming array of diamonds, and closed the pocketbook again. “Well, I guess that’ll be all for to-night, Mister Savnak, and——” His words ended in a sudden gasp.

Billy Kane was standing in the doorway, his automatic covering the men.

“Don’t move, please, any of you!” Billy Kane’s voice, gruffly unrecognizable, was facetiously debonair.

Birdie Rose’s face had gone a pasty white; Savnak, hunched in his chair, stared helplessly; Red Vallon, his jaw dropped, still holding the pocketbook, found his voice.

“The man in the mask!” he mumbled.

“I was a little late for the tombola myself at Vetter’s to-night,” said Billy Kane coolly. “I understand you were all there. I only got as far as the back yard when the gathering broke up, and I was a little disappointed because I had a hunch that I held the winning number. However, if you, there, with the pocketbook, whatever your name is, will just toss the prize over here, I’m willing to overlook any slight irregularity there might have been in the drawing.”

Red Vallon did not answer.

The muzzle of Billy Kane’s automatic lifted to a level with the gangster’s eyes.

“Did you hear me?” The facetiousness was gone from Billy Kane now. His voice rasped suddenly. “Toss it over!”

With an oath, Red Vallon flung the pocketbook over the table.

Billy Kane caught it deftly with his left hand.

“Thank you!” said Billy Kane politely. He tucked the chamois case into his pocket, and reached out for the doorknob. “I think that is all—gentlemen,” he said softly; “except to wish you—good-night!”

In a flash he had shut the door upon them, and, turning, was running across the outer room. But Red Vallon, too, was quick. Before Billy Kane reached the door leading into the hall, he heard the window of the front room flung up—and Red Vallon’s voice:

“Quick, boys, come in! The man in the mask! Head him off! Jump for it! He’s going downstairs!”

Billy Kane’s jaws clamped hard, as he swung through the door to the head of the stairs. It was true! He remembered that Red Vallon had said he had some of his gang with him. He could hear them now. They were running into the lower hall; and, though he was taking the stairs three and four at a time, they would meet on the lower staircase, if he kept on. His escape was cut off. There was only one chance—Peters’ door—it was unlocked—Peters’ door, before Red Vallon above opened the door of Savnak’s flat and saw him.

It had been a matter of seconds, no more; but seconds that had seemed of interminable duration. He was at the foot of the stairs now. Came the pound of approaching feet from below. Red Vallon, whether because he had not had time, or because he was wary of a trap, had not opened the door into the hall above yet. Billy Kane, cautious of any sound, slipped through the door into Peters’ flat, half drew back in sudden dismay—then grimly closed the door behind him softly, and, working with desperate haste now, and still silently, took out his skeleton keys and locked it. He turned, then, with his automatic flung out in front of him—and faced toward the door that opened on his left. He knew it, of course! But it had been too late to turn back. He was doubly trapped! His lips, thinned, curved in a bitter smile. If there was any murder to be done here in this flat to-night, it was likely now to be his own—not Peters’! There was a light in that room! Peters must have come in while he, Billy Kane, was upstairs. He was between two fires. A cry, any alarm given by Peters, would bring Red Vallon and his blood-fanged pack bursting through that door behind him. Was Peters deaf? True, he, Billy Kane, had slipped as silently through the door as he could, and had locked it as silently as he could, but he must have made some noise!

Feet raced by in the hall, and went thumping up the stairs. It was strange that Peters had not heard him! It was stranger still that Peters did not hear the commotion now that Red Vallon’s pack was making!

Billy Kane moved forward stealthily until he could see into the lighted room—and stood suddenly still. He felt the blood leave his face. He lifted his hand to his eyes in a queer, jerky, horrified motion; and then, with a low cry, he ran forward into the other room. The place was in confusion. It was a bedroom, and bureau drawers had been wrenched out and thrown around; every possible receptacle that might have concealed the smallest object had been ransacked and looted, and the contents strewn in wild disorder everywhere about—and on the floor a man lay sprawled, dead, murdered, a brutal wound in the side of his head from a blow that had apparently fractured the skull.

He knelt for a moment over the man. It was Peters. He rose, then, and stood there, fighting to rouse his brain from blunted torpor, to force it to resume its normal functions. Peters had been lying here dead, all the time that he, Billy Kane, had been waiting outside there in the hall! It must have taken quite a little while to have accomplished this murder and ransack the room. Peters, therefore, must have left the Ellsworth house earlier than usual, since the murderer, allowing for the length of time he would have required for his work, must have completed it and made his escape before he, Billy Kane, had arrived here at nine o’clock. It was very strange, horribly strange—to find Peters murdered! Who was it, who had done it? Who was it, other than himself, who could have had any motive? What did it mean? What was it that Peters had had here, that had been the object of such a frantic search? Billy Kane drew his breath in suddenly, sharply. What could it be save one thing! The Ellsworth rubies! That was it, wasn’t it—rubies!

A sound from somewhere out in the hall brought surging back upon him a realization of his own imminent peril. There must be some way out, he must find a way. If he knew Red Vallon at all, he knew that he, Billy Kane, would never leave by the door! Well, a fire escape then, perhaps!

Quick now, every faculty alert, he ran noiselessly from room to room, and from window to window. He returned a moment later to the hall door, his face a little harder set and strained. There was no escape by the windows. There was nothing, except an increasing sound of disturbance that seemed to be affecting all parts of the house. Nothing, save Red Vallon’s voice just outside the door, talking, evidently, to some of his men:

“He ain’t got out—and he ain’t going to get out till we’ve searched every flat in the place! He’s most likely on this floor, and Birdie and me’ll tackle this door here first; but you go down there and tell those people below to shut up their row, and some of you look through their rooms. Beat it!”

Footsteps scurried away. The doorknob was tried. Billy Kane’s lips were a thin line. There was no physical way of escape. Was there a way of wits? His wits against Red Vallon’s! He stood there motionless, a queer, grim look creeping into his face, as the door now was shaken violently. And then, suddenly, he jerked his mask from his face, and thrust it into his pocket. Yes, there was a way, but a way that held a something of ghastly, abysmal irony in it. He could prove an alibi—he had a witness to it.

The door quivered, but held, under a crashing blow. Then Red Vallon’s growling voice:

“Get out of the road, Birdie, and let me at it! I’ll bust it in!”

And then Billy Kane spoke.

“Is that you, Red?” he demanded harshly.

There was a surprised gasp from the hall without, a second’s tense silence, and then Red Vallon’s voice again, heavy with perplexity and amazement:

“Who in hell are you?”

Billy Kane unlocked the door, flung it open, and stepped back. The hall had been lighted now, evidently to facilitate Red Vallon’s search, and the light fell full upon Billy Kane through the doorway.

“The Rat!” The gangster’s little red-rimmed eyes blinked helplessly—then suddenly narrowed. “What are you doing here?”

“You fool!” snarled Billy Kane angrily. “I thought I recognized your voice! You gave me a scare! What are you doing here? What’s all this cursed noise about?”

“What’s it about?” repeated Red Vallon mechanically. He spoke automatically, as though through force of habit at the Rat’s command. “The Mole lives upstairs. He got those diamonds from Vetter; then Birdie and me took ’em from him, and not five minutes ago that blasted man in the mask turned the trick on us, and”—his voice changed with a jerk, and became suddenly truculent—“it’s damned funny where he got to!”

“Come in here, both of you!” ordered Billy Kane peremptorily. “Come in here, and shut that door! Now”—as they obeyed him—“that’s the story, is it, Red? Well, listen to mine!” His voice grew raucous, menacing, unpleasant. “This is the second time to-night you’ve run foul of my plans with your infernal diamonds and your piker hunts, and if trouble comes from this, look out for yourself! Five minutes ago, you said. Well, I wish he’d beaned you while he was at it! You’ve put an hour’s work of mine to the bad! How long do you think this disturbance is going on, before the police butt in? Take a look in that room, there!”

The two men took a step forward, and shrank suddenly back. Birdie Rose’s face had gone gray. He looked wildly at Billy Kane.

“My Gawd!” whispered Red Vallon.

“I said something to you to-night about needing an object lesson, so that it would sink into you that when I said the limit I meant it,” said Billy Kane evenly. “Well, you’ve got it now! Do you know who that man is?”

Red Vallon shook his head. Birdie Rose was nervously plucking at a package of cigarette papers that he had drawn from his pocket.

“His name is Peters,” said Billy Kane curtly. “Peters was the butler at Ellsworth’s. Jackson’s pal. Get me? I found this”—the ruby, from his vest pocket, was lying now in the open palm of Billy Kane’s hand. “Do you understand what ‘limit’ means now, Red? I found this. He wouldn’t talk, and so——” Billy Kane shrugged his shoulders coolly, and his hand jerked forward, pointing to the disordered room. “I hadn’t found any more of them when you messed it up with your noise.”

Red Vallon circled his lips with his tongue.

“Let’s get out of here!” he said hoarsely.

“We’ll have to now, thanks to you!” snapped Billy Kane shortly. “That’s the only room that’s been searched, and you’ve queered any chance of doing anything more now.” He whirled impetuously on Red Vallon, and shook his fist in the gangster’s face. “You see what you’ve done! Even if the police haven’t got wise to the row, those people in the apartments downstairs will call them in the minute they get a chance. Yes, we’ve got to beat it! You and your diamonds are likely to give us a ride by the juice route up in that little armchair in Sing Sing. If your man gets away it’s a small matter now. Anybody that’s caught here will have to stand for—this. You go first, Birdie, and call the crowd off, and scatter the minute you’re outside the house. I don’t want it published in the papers that I was with Peters in his expiring moments! Tumble? I can trust you two, because”—Billy Kane’s smile was unhappy—“if anything leaks, I’ll know where it leaked from! Get the idea? Now, beat it, Birdie! We’ll give you a couple of minutes ahead of us.”

The man went out. Billy Kane walked coolly to the door, took the skeleton key from the inside of the lock, and fitted it again to the outside.

“Come on, Red!” he said.

He locked the door, and put the bunch of keys in his pocket. It was comparatively quiet in the house now. A door of one of the lower apartments opened cautiously, but closed instantly again, as Billy Kane, with the gangster beside him, went down the stairs. In another moment they were out on the street, and had turned the first corner.

The gangster was muttering to himself:

“There’s Birdie and me. But Savnak won’t dare let a peep out of him, ’cause he was in on the diamond pinch himself. I’ll get that guy with the mask yet, if I swing for it. Spilled every blasted bean in the bag—that’s me!” His voice took on a sudden, half cringing, half deferential note. “It wasn’t my fault, Bundy—honest! You know that! You ain’t sore, are you, Bundy?”

Billy Kane pushed his hat to the back of his head. The night air was cool, even crisp, but his hatband was wringing wet. He brushed his damp hair back from his forehead. It was strange that he should have murdered Peters, after all!

He answered gruffly.

“Forget it!” said Billy Kane, alias the Rat.