Special Agent K-7 (1936)

Famous criminal lawyer Lester Owens wins the release of his client, Eddie Geller, when Geller's trial ends with a deadlocked jury. A short time later, Vince "Lanny" Landers, F.B.I. Special Agent K-7, returns home from a trip to Europe and is greeted by reporter Olive O'Day, who jokingly tries to convince him to tell her the real story behind his trip. Even though he wants to retire, Landers has agreed to help the F.B.I. crack down on organized crime. After Kennedy, one of Geller's jurors, is found dead with $500 in his pocket, Adams, Landers' supervisor, asks him to find Geller's boss. Hoping to question Geller, Landers accepts Olive's invitation to a party in honor of her and her fiance, Billy Westrop, which Owens is giving that evening at Geller's nightclub. At the club, Landers warns Geller that he will eventually go to jail and suggests that he testify against his boss in exchange for a lighter sentence. During the evening, Geller and Tony Black quarrel over Peppy, a singer who is in love with Tony; Silky Samuels demands payoff money from Geller for fixing the jury; Schmidt, a gambler, accuses Geller of running a crooked game; and Geller demands that Billy pay his gambling debt. Later, when Geller is found dead, all the men become suspects. Olive convinces her newspaper to allow her to follow the story. She recognizes one of Geller's busboys from Geller's trial and tells Landers, who questions him and learns that Geller murdered his father. Olive and Billy get married, but after Tony is found murdered and the police identify Billy's fingerprints on the murder weapon, he is arrested. To help the couple, Landers questions the remaining suspects and Owens agrees to defend Billy. At Billy's trial, Owens uncharacteristically fumbles the defense. Landers then testifies that the fingerprints on the gun were forgeries and forces Owens to admit that he committed the murders and framed Billy because he was in love with Olive. Landers suspicions were aroused when he learned that Owens was an accomplished engraver and thus was capable of forging Billy's fingerprints on the murder weapon.