Below the Deadline (1921)

Wharf-master Buck Elliot is the leader of a band of murderous crooks. The gang shoots down a policeman in a wharf side scuffle, and Detective Donovan swears revenge on the murderer. He follows Elliot home, where Elliot persuades his wife (previously unaware of her husband's underground life) to provide him with an alibi. When Mrs. Elliot is later brought to police headquarters, incriminating evidence indicating Elliot's complicity in a scheme for a train robbery is disclosed. Under Donovan's leadership the police catch the thieves in the act. Elliot escapes but is later pursued by Donovan, whose life is saved when a fellow policeman shoots and kills Elliot. Over time Donovan and Mrs. Elliot realize they love each other.