“I had meant all along to contrive to be alone in the room sooner or later, and was prepared for the opportunity. I had in my pocket the handle of the paper-maker’s knife and one of the blades. I placed the handle in Mr. Copperdock’s right hand, and pressed the fingers round it. Then I put the blade and handle in the pocket of one of his overcoats, satisfied that sooner or later it would be found there, with his fingerprints upon it. A few minutes later, a chance remark of Inspector Whyland’s gave me a further idea. If the suicide theory were correct, the hypodermic syringe ought to be found. I had, I confess, overlooked this point, but it was readily rectified. Directly he left me, I looked out an old syringe, fitted the other half of the needle to it, and dropped it by the side of the road under Mr. Copperdock’s window. Waters found it within half an hour.