You know what that question was.  I shall have communicated it to you, if you have not already guessed it, before perusing these lines: 

“Who uttered the scream which gave the first alarm of Mr. Hasbrouck’s violent death?”

I was in a state of such excitement as I walked away—­for I listened to my better judgment as to the inadvisability of my disturbing Mrs. Hasbrouck with these new inquiries—­that the perspiration stood out on my forehead.  The testimony she had given at the inquest recurred to me, and I remembered as distinctly as if she were then speaking, that she had expressly stated that she did not scream when confronted by the sight of her husband’s dead body.  But someone had screamed and that very loudly.  Who was it, then?  One of the maids, startled by the sudden summons from below, or someone else—­some involuntary witness of the crime, whose testimony had been suppressed at the inquest, by fear or influence?

The possibility of having come upon a clue even at this late day so fired my ambition that I took the first opportunity of revisiting Lafayette Place.  Choosing such persons as I thought most open to my questions, I learned that there were many who could testify to having heard a woman’s shrill scream on that memorable night, just prior to the alarm given by old Cyrus, but no one who could tell from whose lips it had come.  One fact, however, was immediately settled.  It had not been the result of the servant-women’s fears.  Both of the girls were positive that they had uttered no sound, nor had they themselves heard any till Cyrus rushed to the window with his wild cries.  As the scream, by whomever given, was uttered before they descended the stairs, I was convinced by these assurances that it had issued from one of the front windows, and not from the rear of the house, where their own rooms lay.  Could it be that it had sprung from the adjoining dwelling, and that—­

I remembered who had lived there and was for ringing the bell at once.  But, missing the doctor’s sign, I made inquiries and found that he had moved from the block.  However, a doctor is soon found, and in less than fifteen, minutes I was at the door of his new home, where I asked, not for him, but for Mrs. Zabriskie.

It required some courage to do this, for I had taken particular notice of the doctor’s wife at the inquest, and her beauty, at that time, had worn such an aspect of mingled sweetness and dignity that I hesitated to encounter it under any circumstances likely to disturb its pure serenity.  But a clue once grasped cannot be lightly set aside by a true detective, and it would have taken more than a woman’s frowns to stop me at this point.

However, it was not with frowns she received me, but with a display of emotion for which I was even less prepared.  I had sent up my card and I saw it trembling in her hand as she entered the room.  As she neared me, she glanced at it, and with a show of gentle indifference which did not in the least disguise her extreme anxiety, she courteously remarked: