Before a table strewn with papers, in the room we have already mentioned as given over to the use of the police, sat Dr. Heath in a mood too thoughtful to notice the entrance of Mr. Gryce and Sweetwater from the dining-room where they had been having dinner.

However as the former’s tread was somewhat lumbering, the coroner’s attention was caught before they had quite crossed the room, and Sweetwater, with his quick eye, noted how his arm and hand immediately fell so as to cover up a portion of the papers lying nearest to him.

“Well, Gryce, this is a dark case,” he observed, as at his bidding the two detectives took their seats.

Mr. Gryce nodded; so did Sweetwater.

“The darkest that has ever come to my knowledge,” pursued the coroner.

Mr. Gryce again nodded; but not so, Sweetwater. For some reason this simple expression of opinion seemed to have given him a mental start.

“She was not shot. She was not struck by any other hand; yet she lies dead from a mortal wound in the breast. Though there is no tangible proof of her having inflicted this wound upon herself, the jury will have no alternative, I fear, than to pronounce the case one of suicide.”

“I’m sorry that I’ve been able to do so little,” remarked Mr. Gryce.

The coroner darted him a quick look.

“You are not satisfied? You have some different idea?” he asked.

The detective frowned at his hands crossed over the top of his cane, then shaking his head, replied:

“The verdict you mention is the only natural one, of course. I see that you have been talking with Miss Challoner’s former maid?”

“Yes, and she has settled an important point for us. There was a possibility, of course, that the paper-cutter which you brought to my notice had never gone with her into the mezzanine. That she, or some other person, had dropped it in passing through the lobby. But this girl assures me that her mistress did not enter the lobby that night. That she accompanied her down in the elevator, and saw her step off at the mezzanine. She can also swear that the cutter was in a book she carried—the book we found lying on the desk. The girl remembers distinctly seeing its peculiarly chased handle projecting from its pages. Could anything be more satisfactory if—I was going to say, if the young lady had been of the impulsive type and the provocation greater. But Miss Challoner’s nature was calm, and were it not for these letters—” here his arm shifted a little—“I should not be so sure of my jury’s future verdict. Love—” he went on, after a moment of silent consideration of a letter he had chosen from those before him, “disturbs the most equable natures. When it enters as a factor, we can expect anything—as you know. And Miss Challoner evidently was much attached to her correspondent, and naturally felt the reproach conveyed in these lines.”

And Dr. Heath read:

“A threat!”

The words sprang from Sweetwater, and were evidently involuntary. Dr. Heath paid no notice, but Mr. Gryce, in shifting his hands on his cane top, gave them a sidelong look which was not without a hint of fresh interest in a case concerning which he had believed himself to have said his last word.

“It is the only letter of them all which conveys anything like a reproach,” proceeded the coroner. “The rest are ardent enough and, I must acknowledge that, so far as I have allowed myself to look into them, sufficiently respectful. Her surprise must consequently have been great at receiving these lines, and her resentment equally so. If the two met afterwards—But I have not shown you the signature. To the poor father it conveyed nothing—some facts have been kept from him—but to us—” here he whirled the letter about so that Sweetwater, at least, could see the name, “it conveys a hope that we may yet understand Miss Challoner.”

“Brotherson!” exclaimed the young detective in loud surprise. “Brotherson! The man who—”

“The man who left this building just before or simultaneously with the alarm caused by Miss Challoner’s fall. It clears away some of the clouds befogging us. She probably caught sight of him in the lobby, and in the passion of the moment forgot her usual instincts and drove the sharp-pointed weapon into her heart.”

“Brotherson!” The word came softly now, and with a thoughtful intonation. “He saw her die.”

“Why do you say that?”

“Would he have washed his hands in the snow if he had been in ignorance of the occurrence? He was the real, if not active, cause of her death and he knew it. Either he—Excuse me, Dr. Heath and Mr. Gryce, it is not for me to obtrude my opinion.”

“Have you settled it beyond dispute that Brotherson is really the man who was seen doing this?”

“No, sir. I have not had a minute for that job, but I’m ready for the business any time you see fit to spare me.”

“Let it be to-morrow, or, if you can manage it, to-night. We want the man even if he is not the hero of that romantic episode. He wrote these letters, and he must explain the last one. His initials, as you see, are not ordinary ones, and you will find them at the bottom of all these sheets. He was brave enough or arrogant enough to sign the questionable one with his full name. This may speak well for him, and it may not. It is for you to decide that. Where will you look for him, Sweetwater? No one here knows his address.”

“Not Miss Challoner’s maid?”

“No; the name is a new one to her. But she made it very evident that she was not surprised to hear that her mistress was in secret correspondence with a member of the male sex. Much can be hidden from servants, but not that.”

“I’ll find the man; I have a double reason for doing that now; he shall not escape me.”

Dr. Heath expressed his satisfaction, and gave some orders. Meanwhile, Mr. Gryce had not uttered a word.