For instance, the clothing, to which I now turned in my review of the position. If my guess was right, the unknown in Manderson’s shoes had certainly had possession of Manderson’s trousers, waistcoat, and shooting jacket. They were there before my eyes in the bedroom; and Martin had seen the jacket—which nobody could have mistaken—upon the man who sat at the telephone in the library. It was now quite plain (if my guess was right) that this unmistakable garment was a cardinal feature of the unknown’s plan. He knew that Martin would take him for Manderson at the first glance. And there my thinking was interrupted by the realization of a thing that had escaped me before. So strong had been the influence of the unquestioned assumption that it was Manderson who was present that night, that neither I nor, as far as I know, any one else had noted the point. _Martin had not seen the man’s face, nor had Mrs. Manderson._ Mrs. Manderson (judging by her evidence at the inquest, of which, as I have said, I had a full report made by the _Record_ stenographers in court) had not seen the man at all. She hardly could have done, as I shall show presently. She had merely spoken with him as she lay half asleep, resuming a conversation which she had had with her living husband about an hour before. Martin, I perceived, could only have seen the man’s back, as he sat crouching over the telephone; no doubt a characteristic pose was imitated there. And the man had worn his hat, Manderson’s broad-brimmed hat! There is too much character in the back of a head and neck. The unknown, in fact, supposing him to have been of about Manderson’s build, had had no need for any disguise, apart from the jacket and the hat and his powers of mimicry. I paused there to contemplate the coolness and ingenuity of the man. The thing, I now began to see, was so safe and easy, provided that his mimicry was good enough, and that his nerve held. Those two points assured, only some wholly unlikely accident could unmask him. To come back to my puzzling out of the matter as I sat in the dead man’s bedroom with the tell-tale shoes before me. The reason for the entrance by the window instead of by the front door will already have occurred to any one reading this. Entering by the door, the man would almost certainly have been heard by the sharp-eared Martin in his pantry just across the hall; he might have met him face to face.