Fighting Fools (1949)

At the unexpected death of Mrs. Higgins' second son in the boxing ring, Slip sets his gang to find her first son, Johnny Higgins, who left boxing and disappeared following a fixed fight (not of his doing). Slip persuades him to return to the ring, but a crooked deal by the opponent bars Johnny from further fights. A new fight is finally arranged, but it's another rigged deal. To guarantee Johnny's acquiescence, his kid brother is kidnapped and life threatened. Sach come to the rescue.