Riff-Raff is a 1947 black-and-white film starring Pat O'Brien, Anne Jeffreys and Walter Slezak. Considered a minor film noir entry more in the adventure genre, it was directed by Ted Tetzlaff, who also directed The Window (1949) and worked as a cinematographer for over 100 films, including another successful suspense film, Alfred Hitchcock's Notorious (1946). The music was composed by Roy Webb and Joan Whitney.
A cargo plane leaves Peru, bound for Panama with two passengers during a storm. When one of the two pilots goes to check on an opened door, Charles Hasso (Marc Krah) claims he tried but failed to prevent the other passenger from jumping to his death. Upon landing, Hasso is questioned by Major Rues (George Givot) of the Panamanian secret police, but is released as there were no witnesses. Hasso takes with him the deceased's briefcase, in which he finds a map.
Hasso hires private investigator Dan Hammer (Pat O'Brien) to be his bodyguard for a couple of days. While Hammer is changing, Hasso secretly pins the map to Hammer's bulletin board.
Hammer receives an urgent summons from oil executive Walter Gredson (Jerome Cowan), so he arranges to meet Hasso later at his hotel room. Gredson hires Hammer to find Hasso and the map, which shows the locations of unregistered oil wells in Peru that his company has bought.
Later, in a nightclub, Hammer is attracted to singer Maxine Manning (Anne Jeffreys). He invites her to come by his office after work, unaware that she is spying on him for her boyfriend, Gredson. Tourist Eric Molinar (Walter Slezak) tries to hire him as a guide, but Hammer turns him down.
When Hammer goes to see Hasso, he finds Hasso's body in the overflowing hotel room bathtub. As the search for the map continues, Maxine starts falling for Hammer and switches sides. Meanwhile, Molinar reveals that he is also after the map. He has his two thugs try to beat its location out of the detective, but Hammer has no idea where it is.
Molinar and his men later go to question Gredson. Hammer has Maxine telephone the executive to say the map is in Hammer's office. Molinar, listening in, sees no further use for Gredson and has him killed. Then he and his goons go to the office. A fight breaks out, during which Molinar finally spots the map. He hastens away with it in a taxi driven by Pop (Percy Kilbride), Hammer's close friend. Molinar takes Pop's suggestion to hide out for a while, only to find that the driver's directions lead him straight to police headquarters.Pat O'Brien as Dan Hammer
Anne Jeffreys as Maxine Manning
Walter Slezak as Eric Molinar
Percy Kilbride as Pop
Jerome Cowan as Walter Gredson
George Givot as Major Rues
Jason Robards Sr. as Mr. Domingues
Marc Krah as Charles Hasso
The film was based on an original screenplay by Martin Rackin. It was known as The Big Angle. Rackin had previously written two films for Pat O'Brien, Bombadier and Marine Raiders, and he was linked to the project as soon as RKO bought the script. Rackin reportedly wrote the story while serving in the air force.
Ted Tezlaff had started directing before serving in World War Two. When he returned to Hollywood he shot a number of films for RKO but wanted to return to directing. Producer Jack Gross assigned him to Riffraff, although it meant Tetzlaff took a salary cut to get the job.