Jonathan Creek: Mother Redcap (1998)

A judge on a police protection programme is killed by a rapier blade to the heart after a brief struggle, but only his wife, who insists she's innocent, was in the room at the time, and the only evidence at the crime scene is a torn fingernail. As Jonathan investigates the murder, Maddy and a new friend are investigating the derelict Mother Redcap Inn, where seven men apparently died of fright after looking out of a window in the same room. A connection between the cases is drawn when Maddy discovers the body of a vagrant woman... missing a fingernail.