Side Street (1929)

Brothers Jimmy O'Farrell (a police officer) and John O'Farrell (a police surgeon) begin to suspect their brother Dennis is a racketeer after a shooting occurs in front of their parent's brownstone, and John treats the victim of a beating who is found in Dennis' apartment. Dennis' family believes that he is a successful businessman, when in fact, using the alias Barney Muller, he is the leader of the infamous Muller gang. Jimmy is promoted to detective, and so he proposes to his girlfriend, Kathleen. Shortly thereafter, Kathleen attends a party given by "Muller." She learns that Muller's henchman, "Silk," is the gunman involved in the murder that took place in front of the O'Farrell apartment. Kathleen tells Jimmy, but she is overheard by one of Muller's men, and plans are made to dispose of Kathleen and Jimmy. Dennis realizes his cover has been blown, and he learns of the plot against Jimmy. Dennis and John rush to warn Jimmy, but they arrive just as Jimmy is being ambushed. Dennis saves Jimmy, but he is shot in the process of doing so and by his own gang. Dennis dies in the arms of Jimmy and John, who tell their parents that Dennis has gone on another mysterious trip, perhaps this time for good.