Thou Shalt Not Steal (1917)

Mary Bruce is wooed by Lord Haverford but loves Roger Benton, her father's secretary. To finalize his marriage proposal, Lord Haverford offers her father a large sum of money and, being low on funds, Mr. Bruce accepts it, then places it in a safe. Horrified by her father's actions, Mary steals the cash from the safe that night, but on her way out is overcome by another thief whose wrist she bites in the ensuing tussle. When the theft is discovered, Mary, Benton and Mr. Bruce are suspected, but Dr. Steele, a detective, convinces Mary that Haverford, or the man who calls himself Haverford, is the actual thief. Steele tells how the phony Haverford attempted to kill the real one, stole his money, assumed his identity and is now extorting cash from Bruce. With the bitten wrist as proof, Steele exposes the impostor, then reveals himself to be the real Lord Haverford, whose sweetheart has been posing as the Bruces' maid. The mystery resolved, Mary and Benton happily reunite.