Sir Henry is apparently attacked and killed by the hound but the victim is actually an escaped convict, Seldon, Mrs. Barrymore's brother, to whom she had given old clothes of Henry's and the dog, recognizing the scent from the boot stolen in London, had gone for him. Watson meets a disguised Holmes, living rough on the moors in order to survey the likely suspects. He believes he has seen the man who controls the hound and sets a trap for him with Sir Henry as its bait.