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: “Your name is an unfamiliar one to me. But you told my maid that your business was one of extreme importance, and so I have consented to see you. What can an agent from a private detective office have to say to me?” Startled by this evidence of the existence of some hidden skeleton in her own closet, I made an immediate attempt to reassure her. “Nothing which concerns you personally,” said I. “I simply wish to ask you a question in regard to a small matter connected with Mr. Hasbrouck’s violent death in Lafayette Place, a couple of years ago. You were living in the adjoining house at the time I believe, and it has occurred to me that you might on that account be able to settle a point which has never been fully cleared up.” Instead of showing the relief I expected, her pallor increased and her fine eyes, which had been fixed curiously upon me, sank in confusion to the floor. “Great heaven!” thought I. “She looks as if at one more word from me, she would fall at my feet in a faint. What is this I have stumbled upon!” “I do not see how you can have any question to ask me on that subject,” she began with an effort at composure which for some reason disturbed me more than her previous open display of fear. “Yet if you have,” she continued, with a rapid change of manner that touched my heart in spite of myself, “I shall, of course, do my best to answer you.”