Heroes in Blue (1939)

Gangster Moran gives Joe Murphy several thousand dollars to bet on a horse race, the horse wins and Joe takes off with the money. Moran informs Mike Murphy, Joe's father, that no harm will come to Joe if Mike doesn't interfere with the robbing of stores on his beat. Joe's policeman brother, Terry Murphy, learns of the plot and sets out to free his father and brother of Moran's threats.