In The Adventure of the Crooked Man, Holmes and Watson are discussing the murder of Colonel James Barclay. It was said that his wife and he were having an argument in the morning-room, but the maids and coachman had no clue what had happened because the door was locked. The coachman had the idea of running across the lawn and climbed through the open window, only to find his master dead, Mrs. Barclay had fainted and the key was gone. The only logical explanation the police can come up with is that Mrs. Barclay had murdered her husband by hitting him with something in the head.
     After searching the crime scene, Holmes concluded that there was a third person involved, who had climbed through the window. The third person had a pet, that's paw prints could not be identified. Since neither Mrs or Mr. Barclay had the key to the door, that meant the third person had taken it when they had escaped.
     Holmes later interrogated Miss. Morrison, who had been out with Mrs. Barclay before the murder. Miss. Morrison told Holmes that Mrs. Barclay and her had been passing through Hudson street when they met a crippled man with a box, who Mrs. Barclay knew and had thought been dead for a long time. They had stepped aside to talk and Miss. Morrison said that the man was angry as Mrs. Barclay left him and that Mrs. Barclay had told Miss. Morrison not to tell anyone of what happened.
     The man who Mrs. Barclay had talked to was Henry Wood and Holmes claimed that he had followed Mrs. Barclay home after she left him and when he was watching Mr. Barclay and Mrs. Barclay through their window, what ever was in his box got loose, explaining the paw prints and why the key went missing.
     The next day, Holmes and Watson go down to Hudson street to talk to Henry. After hearing Mrs. Barclay is being tried for murder, Henry confessed to being responsible for Mr. Barclay's death. He told them that he had once been Colonel Henry Wood the smartest man in the One Hundred and Seventeenth foot in Bhurtee, India. Mr. Barclay and Henry had both loved Mrs. Barclay, but Mrs. Barclay had only loved Henry, how ever her father wanted her to marry Mr. Barclay. They were stuck in Bhurtee and Henry volunteered to inform General Neill about the problem, but he was betrayed by Colonel Barclay and captured by the enemies.
     Henry admitted to following Mrs. Barclay home, saw her arguing with Mr. Barclay and broke in, influenced by his feelings. The sight of Henry, was such a shock to Mr. Barclay and he died of apoplexy, hitting his head against the table as he fell. Mrs. Barclay fainted and Henry took the key, intending to unlock the door, but ran when he heard noises, afraid he'd be accused of murder. The paw prints belong to Henry's mongoose, Teddy, who had slipped out of his box. Henry was not guilty for killing Mr. Barclay, Holmes said it was basically said it was his way of getting back at Mr Barclay for betraying him.