The Man Who Cheated Himself (1950)

Rich Lois Frazer, divorcing her fortune-hunter husband, finds he's bought a gun. Suspecting he plans to kill her, she calls in her lover, who just happens to be Homicide Lieutenant Ed Cullen. When Ed arrives, the gun gets used...and because of his relationship with Lois, Ed is compelled to compound a felony. The good news: Ed himself is assigned to the case. The bad news: Ed's hotshot younger brother Andy, a new- minted detective, is also on the case...and anxious to prove himself.