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 un.o.bserved, hurried to them. "The envelope is mine."

CHAPTER XX. THE UNKNOWN EQUATION

"No, no," protested Helen vehemently. "You shall not give the envelope to Margaret--you must not."

"It is mine," insisted the widow with equal vehemence.

"Mrs. Brewster." Kent withheld the envelope from both women. "Will you tell me the contents of this envelope?"

"No," curtly. "It is not your affair."

"It is my affair," retorted Kent with equally shortness of manner. "I insist on an answer to my questions in the limousine this morning. How came your handkerchief in Jimmie's possession, and why did you go to the police court and, yet keep your presence there a secret?"

"Jimmie must have picked up the handkerchief when in the McIntyre house," she answered sullenly. "I presume he forgot to provide him self with one in his make-up as burglar. As regards your second question I admit I did go to the police court out of curiosity--I wanted to find out what was going on. You," with a resentful glance at Helen, "treated me as an outsider, and I was determined to find out for myself how the burglar farce would end."

"Ah, you term it a farce--is that why you laughed in court?" asked Kent quickly.

Mrs. Brewster changed color. "I feel badly about that," she stammered.

"I meant no disrespect to Jimmie, but I have a nervous inclination to laugh--almost hysteria--when excited and overwrought."

"I see," answered Kent slowly. He was distinctly puzzled; Mrs.

Brewster's air of candor disarmed suspicion, but--"You saw and talked with Jimmie Turnbull on Monday night?"

"I did not." Her denial was firm.

"Then how did you learn of his arrest?" asked Kent swiftly.

"I overheard him conversing--"

"With whom?" Kent demanded eagerly as she paused as if to reconsider her confidences. Helen, one hand on the desk and the other on the arm of her chair, tried to rise, but her strength had deserted her. "With whom?"

repeated Kent as the widow remained silent.

"Jimmie was talking with Grimes," Mrs. Brewster stated slowly. "From what I overheard, he paid Grimes to let him inside the house."

Kent looked perplexed as he gazed first at the widow and then at Helen, who had sunk back in her chair.

"Mrs. Brewster," he began after a pause. "Who gave Jimmie your aconitine pills which Grimes left on the hall table?"

"The murderer."

"Yes, of course." Kent was watching her closely and he detected the tiny beads of perspiration which were gathering on her upper lip. "And who, in your opinion, was the murderer?"

Mrs. Brewster's expression changed--she looked hunted, and her eyes fell before Kent's; abruptly she turned her back on him, to find Colonel McIntyre at her elbow and Barbara just entering the room. Her eyes traveled past the girl until they rested on Philip Rochester and Detective Ferguson hovering behind him. Her face altered.

"I saw Philip Rochester," pointing dramatically toward him, "crawl out of the reception room window and dart into the street just as O'Ryan came in the front door with Helen."

Detective Ferguson could not restrain a joyful exclamation. "So that was it!" he cried. "You were at the McIntyre house, and gave the poison to Turnbull there--and not in the court room--four hours before he died.

You'll swing for that crime, my buck, in spite of your glib tongue and slippery ways."

As he ceased speaking Ferguson's ever ready handcuffs swung suggestively from his hand, but Helen's agonized cry checked his approach toward Rochester, who stood stolidly waiting for him.

"Father! You cannot permit this monstrous injustice, Philip shall not suffer for another. No, Barbara," as her sister strove to quiet her, "we must tell the truth."

"Suppose I tell it for Colonel McIntyre," Rochester advanced as the door opened and Sylvester ushered in Benjamin Clymer. "You have come in time, Clymer," his voice deepened, the voice of a man accustomed to present a case and sway a court. "Wait, Sylvester, sit at that table and take down these charges--"

"Charges?" questioned Kent, watching his partner narrowly; he tossed a stenographic pad to Sylvester and made a place for him at his desk. "Go on, Rochester; charges against whom?"

"Charges against the man who, occupying a position of trust, planned to swindle the Metropolis Trust Company through forged notes and checks,"

Rochester stated with slow emphasis. "Jimmie Turnbull learned that you, Clymer, were to visit Colonel McIntyre on Monday night, and he went there in disguise to find out if his suspicions were correct. The investigation cost him his life."

Clymer, who had followed Rochester's statement, first with bewilderment and then with rising wrath, found his voice.

"You drunken scoundrel!" he roared. "How dare you!"

"Dare!" Rochester laughed recklessly. "Jimmie kept his wits to the last; his mind was clear; he recognized you in the prisoner's pen and he tried to call you, but his palsied tongue could not say Ben, but stuttered--B--b--b."

"And what did he wish to tell me?" gasped Clymer, down whose colorless face perspiration trickled.

"Aye, what?" broke in Kent significantly.

"Jimmie may not have gotten the information he wished at your house, Colonel McIntyre, but his presence there on Monday night showed the forger he was in danger, and like the human snake he is, he poisoned without warning. Don't move--Sylvester!"

With a backward spring Kent caught his clerk as he sped for the door.

"Don't make any mistake in putting on the handcuffs this time, Ferguson," he shouted. "A forger and a contortionist make a bad customer to reckon with."

CHAPTER XXI. THE RIDDLE ANSWERED

There was absolute stillness in the room; then a babble of exclamations broke out as Sylvester, his expression of dumb surprise giving place to one of fury, struggled to free himself from the detective's firm grip.

"You cannot escape, Sylvester," declared Kent, observing his efforts.

"Your carelessness in using your peculiar gift of penmanship in copying Barbara McIntyre's signature in this memorandum of her visit here"--Kent held up a sheet torn from his pad, "gave me the first clew. These, the second," he showed several pieces of blotting paper freshly used.

"See, in the mirror here is reflected the impression from your clever imitations of the handwritings of Barbara, Colonel McIntyre, and Mrs.