In Puerto Rico to investigate a glut of contraband diamonds that are flooding the world's jewel market, Mr. Moto and his sidekick, a wrestler, find themselves involved in murders by thrown daggers, the frame-up of an overstressed Army colonel, and a pirate gang led by an unknown boss who has inside knowledge of the ensuing investigation.
- Genre: Crime, Mystery, Thriller, Action
- Studio: 20th Century Fox
- Keyword: puerto rico, murder, rescue, shootout, whodunit, dagger, private detective, black stereotype, framed for murder, red herring, knife murder, outlaw gang, police department, army colonel, abduction, secret plan, diamond smugglers, swamp hideout, colonial governor, feigned illness, pro wrestler, launch pursuit
- Cast: Peter Lorre, Warren Hymer, Amanda Duff, Robert Lowery, Leon Ames, Jean Hersholt