Sins of the Night.

Jack Nietsche is a hardened ex-con who now works for an P.I. firm, run by Ted Quincy. Quincy's ex-lover is Roxie, now wife to godfather Tony Falcone. In a huge mix-up/double-cross, Roxie plots with Jack to get rid of Falcone and Quincy, one an abusive husband, the other a demented role playing ex-lover, and run away with Jack. But the double crossings don't end there