Businessman Frank Dean is found dead in his apartment, killed by a blow to the back of the head, with his face and hands burned beyond recognition. Detective Ray Patrick (Paul Langton) arrests Dean's girlfriend, Eden Lane (Barbara Payton), who admits to having struck Dean and is soon convicted of the murder. While Patrick is escorting her to prison, Eden sees a man out the window who she thinks is Dean. She persuades Patrick to help her escape so the two of them can prove her innocence.
Murder Is My Beat contains examples of:
- Blackmail: "Dean" turns out to be a man named Abbott (Roy Gordon), who is still alive. The corpse is that of his chauffeur, Mike, whom he killed for threatening to expose his affair with Eden.
- Character Narrator: Patrick narrates most of the movie.
- Closet Shuffle: Patrick sees a team photo on the wall inside a ceramics factory that he suspects might include Dean. He hides in a closet until the factory closes down for the night so he can steal it in privacy.
- Flashback Effects: The screen ripples as Patrick starts to tell his story. It ripples again, with rising harp notes, when he's done.
- How We Got Here: The film opens with Patrick's friend, Captain Bert Rawley (Robert Shayne), finding Patrick alone in a hotel room and asking what possessed him to help Eden escape.
- I Didn't Mean to Kill Him: Eden admits to hitting Dean with a figurine, but is shocked to learn that the blow killed him.
- I Never Said It Was Poison: Patrick interviews Eden's roommate Patsy Flint (Tracey Roberts), telling her only that he's investigating a homicide. When Patsy guesses that Dean was the murder victim, Patrick says, "Who said Dean was the victim?" Patsy replies, "You. You were the one that was talking about him all evening." Patrick is still suspicious and says, "Jumped to a quick conclusion, didn't you?" Sure enough, Patsy turns out to have been involved in the blackmail operation that led to the man's death, although she didn't kill him.
- Miranda Rights: After Eden admits to hitting Dean, she tries to explain further, but Patrick won't let her until she has a lawyer, saying, "Anything you say can and will be used against you," and explaining that he doesn't want someone locked up without getting a fair shot in court.
