Murder, My Sweet (1944)

Gumshoe Philip Marlowe is hired by the oafish Moose Malloy to track down his former girlfriend. He's also hired to accompany an effeminate playboy buy back some jewels. When the exchange results in the playboy's murder, Marlowe can't leave the case alone, and soon discovers it's related to Malloy's. As he gets drawn deeper into a complex web of intrigue by a mysterious blonde, the detective finds his own life in increasing jeopardy.