Having taken my story so far, I now put forward the following definite propositions: that between a time somewhere about ten, when the car started, and a time somewhere about eleven, Manderson was shot--probably at a considerable distance from the house, as no shot was heard; that the body was brought back, left by the shed, and stripped of its outer clothing, while the car was left in hiding somewhere at hand; that at some time round about eleven o'clock a man who was not Manderson, wearing Manderson's shoes, hat and jacket, entered the library by the garden-window; that he had with him Manderson's black trousers, waistcoat and motor-coat, the denture taken from Manderson's mouth, and the weapon with which he had been murdered; that he concealed these, rang the bell for the butler, and sat down at the telephone with his hat on and his back to the door; that he was occupied with the telephone all the time Martin was in the room; that on going up to the bedroom-floor he quietly entered Marlowe's room and placed the revolver with which the crime had been committed--Marlowe's revolver--in the case on the mantel-piece from which it had been taken; and that he then went to Manderson's room, placed Manderson's shoes outside the door, threw Manderson's garments on a chair, placed the denture in the bowl by the bedside, and selected a suit of clothes, a pair of shoes and a tie from those in the bedroom. Here I will pause in my statement of this man's proceedings to go into a question for which the way is now sufficiently prepared. _Who was the false Manderson?_ Reviewing what was known to me, or might almost with certainty be surmised, about that person, I set down the following five conclusions: (1) He had been in close relations with the dead man. In his acting before Martin and his speaking to Mrs. Manderson he had made no mistake. (2) He was of a build not unlike Manderson's, especially as to height and breadth of shoulder, which mainly determine the character of the back of a seated figure when the head is concealed and the body loosely clothed. But his feet were larger, though not greatly larger, than Manderson's. (3) He had considerable aptitude for mimicry and acting--probably some experience too. (4) He had a minute acquaintance with the ways of the Manderson household. (5) He was under a vital necessity of creating the belief that Manderson was alive and in that house until some time after midnight on the Sunday night. So much I took as either certain or next door to it. It was as far as I could see. And it was far enough. I proceed to give, in an order corresponding with the numbered paragraphs above, such relevant facts as I was able to obtain about Mr. John Marlowe, from himself and other sources. (1) He had been Manderson's private secretary, upon a footing of great intimacy, for nearly three years.