Smashing the Rackets (1938)

Jim 'Socker' Conway, former boxer and FBI hero, is maneuvered for political reasons into a do-nothing job in the district attorney's office. Meanwhile, he meets wild debutante Letty Lane, girlfriend of mob mouthpiece Steve Lawrence; and Letty's much nicer sister Susan. Now the slot machine gang brutally beats Jim's friends Franz and Otto. And Jim finds a way to use his nominal position to go into the racket- busting business. But his success puts Letty in deadly peril...