It still lacked twenty minutes of nine o'clock that night when Harry Kent turned into the Saratoga apartment hotel, and not waiting to take one of the elevators, ran up the staircase to the apartment which had been occupied jointly by Jimmie Turnbull and Philip Rochester. Kent had already selected the right key from among those on the bunch he had found in Rochester's desk at the office, and slipping it into the key-hole of the outer door, he turned the lock and walked noiselessly inside the dark apartment.

The soft click of the outer door as it swung to was hardly noticeable, and Kent, pausing only long enough to get his breath from his run up the staircase, stepped into the living room and reached for the electric light switch. Instead of encountering the cold metal of the switch his groping fingers closed over warm flesh.

Startled as he was, Kent retained enough presence of mind to grasp the hand tightly; the next second a man hurled himself upon him and he gave back. Furniture in the path of the struggling men was overturned as they fought in silent desperation. Kent would have given much for light. He strained his eyes to see his adversary, but the pitch darkness concealed all but the vaguest outline. As Kent got his second wind, confidence in his strength returned and he redoubled his efforts; suddenly his hands shifted their grip and he swung his adversary backward, pinning him against the wall.

A faint, sobbing breath escaped the man, and Kent felt the whole figure against which he pressed, quiver and relax; the taut muscles of chest and arms grew slack, collapsed.

Kent stood in wonderment, peering ahead, his hands empty—the man had vanished!

Drawing a long, long breath Kent felt his way back to the electric switch and pressed the button, lighting both the wall brackets and the table lamps. With both hands on his throbbing temples he gazed at the over-turned chairs; they, as well as his aching throat, testified to his encounter having been a reality and not a fantastic dream. His glance traveled this way and that about the room and rested longest on the opposite side of the room where he had pinned the man to the wall. Wall—! Kent leaned against a tall highboy and laughed weakly, immoderately. He had pushed the man straight against the door leading into Rochester's bedroom, and not, as he had supposed, against the solid wall.

The man had been quick-witted enough to grasp the situation; his pretended weakness had caused Kent to relax his hold, a turn of the knob of the door, which swung inward, and he had made his escape into the bedroom, leaving Kent staring into dark, empty space.

Gathering his wits together Kent hurried into the bedroom—it was empty; so also was the bathroom opening from it. From there Kent made the rounds of the apartment, switching on the light until the place was ablaze, but in spite of his minute search of closets and under beds and behind furniture he could find no trace of his late adversary. Kent stopped long enough in the pantry to refresh himself with a glass of water, then he returned to the living room and sat down in an arm chair by the window. He wanted time to think.

How had the man vanished so utterly, leaving no trace behind in the apartment? The window in Rochester's room was locked on the inside; in fact, all the apartment windows were securely fastened, he had found on his tour of inspection; the only one not locked was the oval, swinging window high up in the side wall of the bathroom; only a child could squeeze through it, Kent decided. The window looked into a well formed by the wings of the apartment house, and had a sheer drop of fifty feet to the ground below.

But for his unfortunate luck in backing the man against the bedroom door instead of the wall he would not have escaped, but how had the man realized so instantly that he was against a door in the pitch darkness? It certainly showed familiarity with his surroundings. Kent sat upright as an idea flashed through his brain—was the man Philip Rochester?

Kent scouted the idea but it persisted. Suppose it had been Philip Rochester awakened from a drunken slumber by his entrance in the dark; if so, nothing more likely than that he had mistaken him, Kent, for a burglar and sprung at him. But why had he disappeared without revealing his identity to Kent? Surely the same reason worked both ways—the man who had wrestled with him was as unaware of Kent's identity as Kent was of his—they had fought in the dark and in silence.

Kent laughed aloud. The situation had its amusing side; then, as recollection came of the scene in the bank that morning, his mirth changed to grim seriousness. At his earnest solicitation and backed by Benjamin Clymer's endorsement of his plan, Colonel McIntyre had agreed to give him until Saturday night to locate the missing securities; if he failed, then the colonel proposed placing the affair in the hands of the authorities.

Kent's firm mouth settled into dogged lines at the thought; such a procedure meant besmirching Jimmie Turnbull's name; let the public get the slightest inkling that the bank cashier was suspected of forgery and there would be the devil to pay. Kent was determined to protect the honor of his dead friend, and to aid Helen McIntyre in her investigation of his sudden death.

Jimmie Turnbull had been the soul of honor; that he had ever stooped to forgery was unbelievable. There was some explanation favorable to him—there must be. Kent's clenched fist struck the arm of his, chair a vigorous blow and he leapt to his feet. Wasting no further time on speculation, he commenced a systematic search of the apartment, replacing each chair and table as well as the rugs which had been over-turned in his recent tussle, after which he tried the drawers of Jimmie's desk. They were unlocked. A careful search brought nothing to light but receipted bills, some loose change, old dinner cards, theater programs, tea invitations, and several packages of cigarettes.

Turning from the desk Kent walked over to the table which he knew was Philip Rochester's property; he recalled having once seen Jimmie place some papers there by mistake; having done so once, the mistake might have occurred again. Taking out his partner's bunch of keys, he soon found one that fitted and opened the drawers. He had half completed his task, without finding any clew to the missing securities, when he was interrupted by the sound of the opening of the front door, and had but time to slam the drawers shut and pocket the keys when the night clerk of the hotel stepped inside the apartment and, closely followed by a sandy-haired man, walked into the living room. He halted abruptly at sight of Kent.

“Good evening, Mr. Kent,” he exclaimed, and took in at a glance the orderly arrangement of the room. “Pardon my unceremonious entrance, but I had no idea you were here, sir; we received a telephone message that a burglar had broken in here.”

“You did!” Kent stared at him. Was he right, after all, in his conjecture; had the man been Philip Rochester? It would seem so, for who else, after taking refuge elsewhere, would have telephoned a warning of burglars to the hotel office? “Have you any idea who sent the message, Mr. Stuart?”

“I have not; it was an out-side call—” Stuart turned to his companion. “Sorry I brought you here on an idiotic chase, Mr. Ferguson.”

“That's all right,” responded the detective good naturedly. “Would you like me to look through the apartment just to see if any one really is concealed on the premises, Mr. Kent?” he asked, and added quickly, seeing Kent hesitate, “I am from the central office; Mr. Stuart can vouch for me.”

Kent's hesitation vanished. “I'd be obliged if you would, Ferguson.” As he spoke he led the way to Rochester's bedroom. “Come with us, Stuart,” as the clerk loitered behind.

“Guess not, sir; I'm needed down at the desk, we are short-handed to-night. Let me know how the hunt turns out,” and he stepped into the vestibule. “Good night.”

“Good night,” called Kent, and he accompanied Ferguson as far as the bathroom door, then returned to his inspection of Rochester's table. He had just completed his task when the detective rejoined him.

“No trace of any one,” the latter announced. “Some one put up a joke on Stuart, I imagine. Find what you wished, sir?”

Kent was distinctly annoyed by the question. “Yes,” he replied shortly.

Ferguson ignored his curt tone. “Will you spare me a few minutes of your time, Mr. Kent?” he asked persuasively. “I won't detain you long.”

“Certainly.” Kent moved over to the chair in the window which he had occupied before and pointed to another, equally as comfortable.

“What can I do for you?” he asked as Ferguson dropped back and stretched himself in the soft depths of the big chair.

“Supply some information,” answered the detective promptly. “Just a minute,” as Kent started to interrupt. “You don't recall me, but I met you while working on the Chase case; you handled that trial in great shape,” Ferguson looked admiringly at his companion. “Lots of the praise went to your partner, Mr. Rochester, but I know you did the work. Now, please let me finish,” holding up a protesting hand. “I know you've carried Mr. Rochester in your firm; he's dead wood.” Kent was silent. What the detective said was only too true. Rochester, realizing the talent and industry which characterized his younger partner, had withdrawn more and more from active practice, and had devoted himself to the social life of the National Capital.

“This is rather a long-winded way of reaching my point,” finished the detective. “But, Mr. Kent, I want your assistance in a puzzling case.”

“Go on, I'm listening.” As he spoke, Kent drew out his cigar case and handed it to Ferguson. “The matches are on the smoking stand at your elbow. Now, what is it, Ferguson?”

His companion did not reply at once; instead he puffed at his cigar.

“Did you read in the paper about Mr. Turnbull's death?” he asked when the cigar was drawing to his satisfaction, and as Kent nodded a silent affirmative in answer to his question, he asked another. “Did you know him well?”

“Yes.”

“Did he have an enemy?”

“Not to my knowledge.” Kent was watching the detective narrowly; what was he driving at? “On the contrary Turnbull was extremely popular.”

“With Colonel McIntyre?” Ferguson had hoped to surprise Kent with the question, but his companion's expression did not alter.

“N-no, perhaps he was not over-popular with the colonel,” he admitted slowly. “What prompts the question, Ferguson?”

The detective hitched his chair nearer. “I'm going to lay all my cards on the table,” he announced. “I need advice and you are the man to give it to me. Listen, Mr. Kent, this Jimmie Turnbull masquerades as a burglar night before last at the McIntyre house, is arrested, a charge brought against him for house-breaking by Miss Helen McIntyre, and shortly after he dies—”

“From angina pectoris,” finished Kent, as the detective paused.

“So Mr. Rochester contended,” admitted Ferguson. “We'll let that go for a minute. Now, when Miss McIntyre saw Turnbull's body, she demanded an autopsy. Why?”

“To discover the cause of death,” answered Kent quietly. “That is obvious, Ferguson.”

“Sure. And why did she wish to discover it?” He waited a brief instant, then answered his own question. “Because Miss McIntyre did not agree with Rochester that Turnbull had died from angina pectoris—that is obvious, too. Now, what made her think that?”

“I am sure I don't know”—Kent's air of candor was unmistakable and Ferguson showed his disappointment.

“Hasn't Miss McIntyre been to see you?”

“No,” was Kent's truthful answer; Barbara was the younger twin and her sister was therefore, “Miss McIntyre.”

“You must recollect, Ferguson,” he added, “that had Miss McIntyre called to see me about poor Turnbull, I would not have discussed the interview with any one, under any conditions.”

“Certainly. I am not asking you to break any confidences; in fact,” Ferguson smiled, “I must ask you to consider our conversation confidential. Now, Mr. Kent, does it not strike you as odd that apparently the only man in Washington who really disliked Turnbull was Colonel McIntyre, and it is his daughter who intimates that Turnbull's death was not due to natural causes?”

“Oh, pshaw!” Kent shrugged his shoulders. “You are taking an exaggerated view of the affair. Colonel McIntyre is an honorable upright American, and Turnbull was the same.”

“People speak highly of both men,” acknowledged the detective. “I saw Mr. Clymer, president of Turnbull's bank this afternoon, and he paid a fine tribute to his dead cashier.”

Kent drew an inward sigh of relief. Benjamin Clymer had proved true blue; he had not permitted Colonel McIntyre's desire for immediate publicity and belief in Turnbull's guilt to shake his faith in his friend.

“You see, Ferguson, there is no motive for such a crime as you suggest,” he remarked.

“Oh, for the motive,”—Ferguson rubbed his hands nervously together as he shot a look at his questioner; the latter's clear-cut features and manly bearing inspired confidence. “We know of no motive,” he corrected.

“And we know of no crime having been perpetrated,” rapped out Kent. “Come, man; don't hunt a mare's nest.”

“Ah, but it isn't a mare's nest!” Ferguson remarked dryly.

Kent bent eagerly forward—“You have heard from the coroner—”

“Not yet,” Ferguson jerked forward his chair until his knees touched Kent.

Had either man looked toward the window near which they were sitting, he would have seen a black shadow squatting ape-like on the window ledge. As Kent leaned over to relight his cigar, the face at the window vanished, to cautiously reappear a second later.

“The case piqued my interest,” continued the detective after a pause. “And I made an investigation on my own hook. After the departure of the McIntyre twins and Coroner Penfield, I went back to the court room and poked around the prisoners' cage. There I found this.” He took out of his pocket a small bundle and carefully unwrapped the oil-skin cover.

“A handkerchief?” questioned Kent as the detective did not unfold the white muslin, but held it with care.

“Yes. One of the prisoners in the cage told me Turnbull dropped it as Dr. Stone and the deputy marshal carried him into the ante-room. Smell anything?” holding up the handkerchief.

“Yes.” Kent wrinkled his nose and sniffed several times. “Smells like fruit.”

Ferguson nodded. “Good guess; I noticed the odor and went at once to Dr. McLane. He told me the handkerchief was saturated with amyl nitrite.”

“Amyl nitrite,” repeated Kent reflectively. “It is given for angina pectoris.”

“Yes. Well, in this case it was the remedy and not the disease which killed Turnbull,” announced Ferguson triumphantly.

“Nonsense!” ejaculated Kent. “I happen to know that the capsules contain only three minims—I once heard Turnbull say so.”

“True, but Turnbull got a lethal dose, all right; and he thought he was taking only the regular one. Devilishly ingenious on the part of the criminal, wasn't it?

“Yes. Have you detected the criminal?” Kent put the question with unmoved countenance, but with inward foreboding; the detective's mysterious manner was puzzling.

“Not yet, but I will,” Ferguson hesitated. “The first thing was to establish that a crime had really been committed.”

Kent bent down and sniffed again at the handkerchief to which a faint fruity aroma still clung.

“How did you discover that?” he asked.

“Dr. McLane and I took the handkerchief to a laboratory and the chemist found from the number of particles of capsules in the handkerchief, that at least two capsules—or double the usual dose—had been crushed by Turnbull and the fumes inhaled by him; with fatal results.”

“Hold on,” cautioned Kent. “In the flurry of the moment, Turnbull may have accidentally put two capsules in the handkerchief, meaning only to use one.”

“Mr. Kent,” the detective spoke impressively, “that wasn't Turnbull's handkerchief.”

“Not his own handkerchief!” exclaimed Kent. “Then, are you sure that Turnbull used it?”

“Yes; that fact is established by reputable witnesses; Dr. Stone, Mr. Clymer, and the deputy marshal,” Ferguson spoke with increasing earnestness. “That is a woman's handkerchief—look at it.”

Ferguson laid the little bundle on the broad arm of Kent's chair and with infinite care folded back the edges of the handkerchief, revealing as he did so, the small particles of capsules still clinging to the linen. But Kent hardly observed the capsules, his entire attention being centered on one corner of the handkerchief, which had neatly embroidered on it the letter “B.”