The Big Heat (1953)

A police officer seems to have committed suicide, but Detective Dave Bannion (Glenn Ford) thinks there's more to the story. After talking to the man's mob-connected mistress, Bannion discovers far-reaching corruption that leads all the way from the police station to kingpin Mike Lagana (Alexander Scourby). But when the policeman's lover is killed, it becomes clear that crossing Lagana is a dangerous thing to do. Soon Bannion finds himself marked for death and his family in mortal danger.