In the Post-World War II, in Los Angeles, a criminal shots and kills a police officer in the middle of the night. Without any leads, the chief of the LAPD assigns Sgt. Chuck Jones and Sgt. Marty Brennan to investigate the murder and apprehend the culprits. When the dealer of electronics devices, Paul Reeves, is caught selling a stolen projector, the police identifies the criminal, and connects him to other unsolved robberies. Using the witnesses of his heists, they draw their face, but the true identity of the smart and intelligent criminal is not disclosed. The perseverance of Sgt. Marty Brennan in his investigation gives a clue where he might live. Technical advisor for the film was Sgt. Marty Wynn of the Los Angeles Police Dept. During the course of shooting he fell into conversation with Jack Webb, then the star of radio’s “Jeff Regan, Private Investigator”, who had a small part in the film. Wynn suggested that Webb do a radio series based on actual police files. Thus was born the idea for “Dragnet,” which debuted on NBC radio about four months after this film was released. This was an historical film in that it was the first to use the Los Angeles underground sewer and storm-drain system and its series of canals and tunnels as a backdrop.