“Ah,” I exclaimed angrily, “then you deceived me——”
“Gently, gently, young man; I don’t deceive anybody. I told you that I wished the young lady well; so I do—that I believed in her innocence; I still do so. I said that the information I had received from you materially helped her case, which it most assuredly did. Had you withheld certain facts it would have been my duty—my painful duty, I acknowledge—to have arrested Miss Derwent last Saturday.”
“But why?” I inquired.
“Because all the evidence pointed towards her, and because my belief in her innocence rested on no more solid foundation than what is called intuition, and intuition is a quicksand to build upon.”
“But what was there to point to her except that a negro boy thought that the dead man resembled Greywood?”
“Ah, you acknowledge that her visitor was Mr. Greywood?”
“Yes, I grant you that, but what of it? I am convinced he has not been murdered.”
“But why?” demanded the detective. “Now, listen to this. The body is identified by two people as Greywood’s. Greywood disappears at about the same time that the crime was committed. We know that the corpse must have been hidden somewhere in the Rosemere for twenty-four hours. Where could it have been more easily secreted than in the Derwents’ apartment, into which no outsider or servant entered? And lastly, it would have required two people to carry, even for a short distance, a body of its size and weight; but as the young lady was not alone, but had with her the man and woman whom you saw, this difficulty is also disposed of. From all this, I conclude that the Derwents’ flat was the scene of the tragedy.”
“But why should Greywood have been killed?” I asked. “What possible motive could there have been?”
“Oh, it is easy enough to imagine motives, although I do not guarantee having hit on the right one. But what do you think of this for a guess? Miss Derwent, who knows that her brother may any day be in need of a hiding-place, has given him the key to their back door. Coming to town, she meets Greywood, dines with him, and invites him to spend the evening with her (having some reason for supposing that her brother is safely out of the way). During this visit they have a violent quarrel, and, in the midst of it, young Derwent, who has come in through the kitchen, suddenly appears. Let us also presume that he is intoxicated. He discovers his sister alone with a man, who is unknown to him, and with whom she is engaged in a bitter dispute. The instinct to protect her rises within him. His eyes fall on a weapon, lying, let us suppose, on the parlour table. He seizes it, and in his drunken rage, staggers across the room and plunges it into Greywood’s heart. What girl could be placed in a more terrible position? She is naturally forced to shield her brother. So she hits on a plan for diverting suspicion from him, which would have been successful, if Fate had not intervened in the most extraordinary way. You remember, that it came out that on Wednesday she went in and out of the building very frequently. During one of these many comings and goings, she manages to extract the key of the vacant apartment, to have it copied, and to return it without its absence being noticed. They then wait till the early hours of the morning before venturing to move the body, which they carry to the place where it was found. Unfortunately for them, they locked the dead man in, and in this way rendered their detection much more easy. For it limited the number of suspected persons to three—to the three people, in fact, who could have had the key in their possession, even for a short time. On returning to their own rooms, they discover that they have lost something of great importance. The young man searches for it long and vigorously. He does not find it——”