Charles Bower

In the short story The Adventure of the Sinister Stranger, Charles Bower (real name Carl Bauer) claims to be a doctor with a surgery and home in Hampstead. He shares his home with his two nephews Bertram and Henry.

In reality Mr Bauer is in league with "Inspector Dymchurch", and they are trying to get hold of the blue letter with a Russian stamp that was sent to The International Detective Agency.