"Thorpe appears to suspect that fellow Short," he remarked, when I met him again in the library a quarter of an hour later. "I've just been chatting with him, and to me his demeanour is not that of a guilty man. He's actually been upstairs with the coroner's officer in the dead man's room. A murderer generally excuses himself from entering the presence of his victim."
"Well," I exclaimed, after a pause, "you know the whole circumstances now. Can you see any clue which may throw light on the affair?"
He slowly twisted his moustache again; then twisted his plain gold ring slowly round the little finger on the left hand--a habit of his when perplexed.
"No, Ralph, old chap; can't say I do," he answered. "There's an unfathomable mystery somewhere, but in what direction I'm utterly at a loss to distinguish."
"But do you think that the assassin is a member of the household? That seems to me our first point to clear up."
"That's just where we're perplexed. Thorpe suspects Short; but the police so often rush to conclusions on a single suspicion. Before condemning him it is necessary to watch him narrowly, and note his demeanour and his movements. If he is guilty he'll betray himself sooner or later. Thorpe was foolish to take down that knife a second time. The fellow might have seen him and had his suspicions aroused thereby. That's the worst of police inquiries. They display so little ingenuity. It is all method--method--method. Everything must be done by rule. They appear to overlook the fact that a window in the conservatory was undoubtedly left open," he added.
"Well?" I asked, noticing that he was gazing at me strangely, full in the face.
"Well, has it not occurred to you that that window might have been purposely left open?"
"You mean that the assassin entered and left by that window?"
"I mean to suggest that the murder might have been connived at by one of the household, if the man we suspect were not the actual assassin himself."
The theory was a curious one, but I saw that there were considerable grounds for it. As in many suburban houses, the conservatory joined the drawing-room, an unlocked glass door being between them. The window that had been left unfastened was situated at the further end, and being low down was in such a position that any intruder might easily have entered and left. Therefore the suggestion appeared a sound one--more especially so because the cook had most solemnly declared that she had fastened it securely before going up to bed.