In the summer of 1919, a young woman named Bella Wright was found dead on a quiet country lane in Leicestershire, a bullet wound in her head. The only clue? A mysterious, well-dressed man seen with her shortly before her death, riding a distinctive green bicycle.

This episode explores one of Britain's most enduring unsolved murders. We trace the police investigation that led to the arrest of a respectable schoolteacher, and the sensational trial that followed. Was it a tragic accident, or a calculated murder?