How does Sherlock Holmes capture the criminal in "The Adventure of the Empty House?"

 

In order to apprehend the criminal involved in the murder of Ronald Adair, Sherlock first pretends to be dead then later comes back and asks for help from his friend Watson.

Holmes knowing that his rooms have been watched ever since he disappeared, places a waxwork which depicts a clear outline of Holmes silhouetted in the window. For many hours, Holmes and Watson watch their old rooms until the silence is broken by the entry of a man into the rooms. The window of the room is then opened, and a strange looked gun is put together. Then there is an almost inaudible sound of a shot being fired. At that very moment, Holmes and Watson leap into action, jumping on the shooter, with Watson laying the man out cold with the butt of his gun.

Holmes whistles for assistance, with the whistle bring forth uniformed policeman as well as Inspector Lestrade.Holmes explains that the shooter shot Adair through the open window and the evidence of the gun and bullets are enough for a conviction.