Harry Kent inserted his key in his office door with more vigor than good judgment, and spent some seconds in re-adjusting it in the lock. Once inside the office he put up the latch and closed the door. A glance around the empty office showed him that Sylvester had obeyed his telephone instructions and gone out to luncheon.

Kent noted with satisfaction as he put his hat and cane in the coat closet that he had over two hours before Mrs. Brewster's expected arrival; ample time in which to consider in quietude the events of the past few days, and plan for his interview with the pretty widow. He had spent the time between Rochester's sudden reappearance and a hastily swallowed lunch at a downtown cafe, in arranging bail for Rochester. Ferguson had proved obdurate and had persisted in taking the lawyer to Police Headquarters.

Dr. Stone had accompanied the trio, and his testimony, supported by two chemists, regarding the time required for aconitine poison to act, had gone far to weaken the detective's case against Rochester.

Rochester, to Kent's unbounded astonishment, had appeared indifferent to the whole proceedings; and to his partner's urgent inquiries as to where he had spent the past four days, and why he had disappeared, he had returned one invariable answer.

“I'll explain in good time, Harry,” and it was not until they were leaving Police Headquarters that his apathy vanished.

“When are you to see Mrs. Brewster?” he asked.

“She will be at our office at four o'clock. Say, Phil”—but Rochester, shaking off his detaining hand, darted across the street and sprang into a passing taxi bearing the sign, “For Hire,” and that was the last Kent had seen of his elusive partner.

Kent dropped into his chair and glanced askance at the mail piled in neat array on his desk; he was not in a frame of mind to handle routine office business. Other clients would have to wait until later in the day. A memorandum pad, bearing a message in Sylvester's precise penmanship attracted his wandering attention and he picked it up.

“Mr. Kent:” he read. “Colonel McIntyre called just after I talked with you on the 'phone; he waited in your office for half an hour, then left, stating he would come back. Miss Barbara McIntyre called immediately afterwards, but would not wait more than five minutes. Mr. Clymer came as she was going out and left a note on your desk. I will return soon.

“SYLVESTER.”

Kent laid down the pad and picked up a twisted three-cornered note bearing his name in pencil. Unfolding it, he scanned the hurriedly written lines:

“Dear Kent—McIntyre telephoned there were new developments in the Turnbull affair. Will be back later.

“Yours—

“B. A. CLYMER.”

Kent judged from the use of his initials that Clymer was stirred out of his ordinary calm, nothing else explained his failure to sign his full name, and he wondered what confidences McIntyre had made to the bank president.

Tossing down the note, Kent lighted his pipe, tilted back in his swivel chair, and reviewed the facts which implicated Rochester in Jimmie Turnbull's murder. Rochester's quarrels with Jimmie, his persistent assertion that his friend had died from angina pectoris, his unexplained disappearance on Tuesday night, the fake telegram from Cleveland stating he was there, the withdrawal of his bank deposits, the forged checks, his mysterious visits to his own apartment, when considered together, presented a chain of circumstantial evidence connecting him with the crime. But in the light of Dr. Stone's testimony, the poison “could not have been administered in the glass of water Rochester had given Jimmie in the police court.”

Four hours at least had to elapse before the fatal dose of aconitine could take effect—four hours! Kent told them off on his fingers; it placed the crime in the McIntyre house. Which one of its inmates administered the poison to Jimmie and how had it been done? What motive had prompted the cashier's murder?

It was preposterous to think that either of the twins was guilty of the crime. Helen's devotion to Jimmie, her insistence upon an autopsy being held indicated her innocence. She had stated at the inquest that she had not known the burglar's identity; Kent paused as the thought occurred to him—the twins had swapped identities on the witness stand, and therefore Helen had not been called upon to answer that question! To the best of his recollection she had only been asked if she had recognized Jimmie in the court room and not at her home. But Helen it was who had summoned Officer O'Ryan on discovering the burglar and had him arrested. She surely would never have done so had she guessed his identity.

As for Barbara McIntyre—Kent's heart beat faster at thought of the girl he loved so well. Circumstantial evidence had seemed for a time to involve her in the crime. Grimes' outrageous insinuation that he had been assaulted on account of confiding to her that the box of aconitine pills had been left on the hall table where any one could get them, was the outcome of his battered condition. When physical strength returned, the butler would forget his hallucinations. The handkerchief with its embroidered letter “B,” used by Jimmie to inhale the fumes from his amyl nitrite capsules, was finally traced to its rightful owner—Mrs. Brewster.

And Mrs. Brewster was due in his office within a very short time. Kent's square jaw became more pronounced; she should not leave until she had either confessed her connection with Turnbull's death, or established her innocence. Surely it would be easy for Mrs. Brewster to do so, but—aconitine had been prescribed for her; she was familiar with the poison, she had it at hand, she went to the police court, and kept her trip a secret, and she had laughed when Jimmie was carried dying from the court room. But what motive could have inspired her to murder Jimmie? Was he an old lover—Kent, unable to keep quiet any longer, rose and paced up and down the office, stopping a moment to glance out of the window. As he passed the safe he saw the door was ajar. Kent paused abruptly. Who had opened the safe?

Crossing to the outer office he looked around; no one was there. It flashed into Kent's mind that he had seen Rochester's light top coat and walking stick in the coat closet as he hung up his hat on his arrival, and he again opened the closet door. The coat and stick were still there; so Rochester had come to the office immediately after leaving him, and carelessly left the safe open! Kent smiled in spite of his vexation; the act was typical of his eccentric partner.

Going back to his own office Kent opened the safe and glanced inside. The pigeon holes and compartments appeared untouched, except the door of one small compartment on Rochester's side. An envelope was wedged in such a manner that the small door would not shut and that had prevented the closing of the outer safe door.

Kent, preparatory to shutting the safe, drew out the envelope intending to place it in another pigeon-hole where there was more room. As he turned the envelope over he was thunderstruck to recognize it as the one which Helen McIntyre had placed in the safe on Wednesday morning. He had last seen the envelope lying on the table in the smoking porch of the Club de Vingt, from whence it had mysteriously disappeared, and now it was back again in Rochester's safe!

Had it ever been missing from the safe? The question forced itself on Kent as he returned to his chair, envelope in hand, and sat down before his desk. He had accepted Detective Ferguson's statement that he had removed the envelope from the safe, and therefore had never looked in the compartment where Helen had put it to verify its disappearance.

Ferguson had removed it, Kent concluded as he examined the envelope with more care; it was the identical one, unaddressed, with the same red seal holding down the flap. The same red seal, but with a difference—a corner was missing.

Kent stared at the seal for a moment in doubt, then his fingers sought his vest pocket and fumbled about for a minute. Taking out Mrs. Brewster's check, he laid it on the desk alongside the envelope, unfolded it, and picked out a piece of red sealing wax which had slid inside the check. Kent placed the red wax on the broken section of the seal—it fitted exactly, forming a perfect letter “B.”

Kent sat in dumbfounded silence, regarding the red seal and the envelope. The piece of wax broken off from the seal had caught on his coat sleeve when he had been in the Venetian casket in the library at the McIntyre house. It was proof positive that not only he had been in the casket, but the sealed envelope also. Helen McIntyre had left the envelope in his care. Mrs. Brewster and Colonel McIntyre had both been present when the envelope was stolen from him. Which of them had taken it? Which one had afterwards secreted it in the Venetian casket? And which had brought it back to the safe in his office?

Colonel McIntyre had been in his office within the hour—the question was answered, and Kent's eyes brightened, then clouded—Barbara had been there as well, and Grimes had stated that before he received a knock-out blow in the McIntyre library he heard the swish of skirts!

Kent laid his hand on the envelope. It was time that he found out what it contained; but his finger, inserted under the flap, paused as his eyes fell on the check bearing Mrs. Brewster's signature. It was the check he had picked up from the floor of the McIntyre limousine that morning and inadvertently carried away with him.

From her signature his glance wandered to Sylvester's memorandum pad; it was uncanny the way his eye picked out the letter “B” as he stared at Clymer's note and its signature. Slowly his hand dropped away from the envelope and he left it lying forgotten on the desk as he picked up piece after piece of blotting paper, glancing intently at each and finally, pulling open a drawer of his desk, he hunted in feverish haste for a hand-mirror.

Some ten minutes later Kent rose, placed the papers he had been examining in the inside pocket of his coat and, using the private entrance from his office into the corridor, he hurried away.

When Helen McIntyre entered the office of Rochester and Kent for the second time that afternoon she found Sylvester transcribing stenographic notes on his typewriter.

“Mr. Kent is expecting you, miss,” he said, holding open the inner office door, and with a courteous word of thanks, Helen passed the clerk and the door closed behind her. Kent rose at her approach and bowed formally.

“Take this chair,” he suggested, and not until she was seated did Helen realize he had placed her where the light fell full upon her. “I asked you to come here,” he began, as she waited for him to speak, “Because I must have your confidence—if I am to aid you. Did you meet, recognize, and talk to Jimmie Turnbull in your house sometime between Monday midnight and his arrest on Tuesday morning?”

She colored hotly, then paled. “My testimony at the inquest,”—she commenced, but he gave her no opportunity to add more.

“Your testimony there does not cover the question,” he explained. “You stated then that you had not recognized Jimmie in the court room. Had you already penetrated his disguise at your house?”

“And if I had?”

“Did you?” Kent was doggedly persistent, and Helen's fingers closed around her handbag with convulsive force. Why had she not sent Barbara to see Kent in her place?

“Did I what?” she parried.

“Did you recognize and talk with Jimmie Turnbull in your house?”

“I talked with him, yes,” she admitted, and her voice dropped almost to a whisper.

“As Jimmie Turnbull or Smith the burglar?”

“As Jimmie”—she confessed, after a slight pause.

“Then why did you go through the farce of having Jimmie arrested as a burglar?” Kent demanded.

“So that Barbara might win her wager,” promptly. Kent stared at her incredulously.

“Do you mean that, notwithstanding the risk to which you were subjecting him with his weak heart, you kept up the farce simply that Barbara might win an idiotic wager?” Kent asked.

Helen passed one nervous hand over the other; her palms were hot and dry, and two hectic spots had appeared in each white cheek.

“Jimmie was quite well Monday night,” she protested. “He—he—had some heart medicine with him.”

“Amyl nitrite?”

“No.”

“Nitro-glycerine?”

“I—I think that was it, I am not quite sure,” she spoke with uncertainty, and Kent knew that she lied. His heart sank.

“Did he swallow any medicine in your presence?”

She shook her head vigorously. “No, he did not.”

Kent lowered his voice. “Did you see him take Mrs. Brewster's aconitine pills off the hall table?”

Helen shifted her gaze to his face and then back to her ever restless hands. “No,” she said. “I did not see him take the pills.”

Kent studied her in a silence which, to her, seemed never-ending.

“I want the true answer to this question,” he announced with meaning emphasis. “Why did Jimmie go in disguise to your house on Monday night?”

Helen blanched. “How should I know,” she muttered evasively. “He—he didn't come to see me—the admission was barely above a whisper.

“But you know what transpired in your house on Monday night?” demanded Kent eagerly.

His question met with no response, and he repeated it, but still the girl remained silent. Kent gave her a moment's grace, then drawing out the unaddressed envelope from his pocket he held it toward her. A low cry broke from her, and her expression changed as she caught sight of the broken seal.

“You have opened it!”

“Not yet,” Kent held the envelope just beyond her reach. “I will only give it to you with the understanding that you open the envelope now in my presence and let me see its contents.”

Helen drew back, then impulsively extended her hand.

“I agree,” she said. “Give me the envelope.”

“Stop!” The word rang out, startling Kent as well as Helen, and Mrs. Brewster, whose noiseless entrance a few seconds before had gone unobserved, hurried to them. “The envelope is mine.”