Lodger

Her pen name was Belloc Lowndes. Lowndes was an early 20th century British novelist. A Jack the Ripper type murderer was killing young blonde women in the London fog. When a lodger comes to the Bunting house their daughter is taken with this mysterious man. Her boyfriend is a detective assigned to the murder cases. He is jealous and suspicious of the stranger. In the conclusion the stranger is forced to flee and is almost killed by a mob when a policeman arrives with the truth about the killings. This novel became a movie directed by Alfred Hitchcock.