Cast & Crew
Jack La Rue
After battalion chief Riley of the New York City Fire Department dies in a fire set by arsonists, his friends, Captain Bill O'Connell and Tom Jones, look after his twelve-year-old son Jimmy. Although Bill is offered Riley's job, he prefers to transfer to the arson squad to find out who was responsible for the chief's death. Although Bill is able to determine that the arsonist is a chemist named Rogers, his case is ruined by reporter Joan Lawrence, who prints his facts in the newspaper before the case can be closed. Bill's superiors blame him for the failed conviction and Bill, in turn, blames Joan. Angered over the case, Bill takes a swing at fire commissioner Benton, then resigns and severs his friendship with Tom and Jimmy. Bill then tells Bud Morgan, a known cohort of Rogers, who has been reported missing, that he knows enough about arson to set fires that will never be detected by the fire department or any insurance company. To prove his point, he sets fire to a small piece of property he owns. Athough the insurance company warns Bill that they are suspicious, Morgan is impressed and hires Bill to work with him setting fires for insurance. Bill's extensive knowledge of chemicals enables him to get away with setting a number of fires, none of which the fire or police departments can prove were arson. Though Tom, Jimmy and Joan try to stop Bill, nothing they say will dissuade him and most of his friends think he has turned crooked. Bill, however, has been secretly working with Commissioner Benton to infiltrate the gang. Bill tells Benton the address of a large fire that will be set that night, in the hopes of finally stopping the gang, but by attempting to help Bill, Tom accidentally tips off Morgan and reveals Bill's real purpose. Morgan then secretly changes the location of the fire. When they reach the new location, Morgan has Bill bound and left in the building to be burned during the fire. Meanwhile, however, Jimmy and Joan have discovered that the gang's leader is Hamilton, head of the insurance company. Although Joan is captured while eavesdropping on Hamilton, Jimmy manages to escape after hearing the real address of the fire. He sneaks into the building just as the fire starts and is able to release Bill just in time. Bill then goes to Hamilton's office while Jimmy summons the commissioner and, after a fight, Bill corners Hamilton and holds him until the police arrive. Finally, Bill is appointed new battalion chief and he and Joan decide to marry.
Jack La Rue
John Victor Mackay
According to a news item in Hollywood Reporter, the working title of the film was Fire Over the Waterfront, and the property was re-activated by Republic in October 1937 after six months "on the shelf." At that time, the announced writers were Joseph K. Watson and Miriam Geiger, however, they were not in the onscreen credits, Screen Achievements Bulletin or any reviews, and it has not been determined whether or not they actually worked on the film. According to a letter from Republic Pictures dated May 9, 1938 contained in the AMPAS library file on the film, its title was changed from Fire over the Waterfront to Arson Gang Busters, the title for copyright number LP7997, and the title under which several sources reviewed it. The film was also copyrighted under the title Arson Racket Squad on the same copyright date, March 22, 1938, under number LP8037. That title appeared on the viewed print. A news item in Hollywood Reporter on February 25, 1938 noted that Capital Punishment was to be the new title of Fire over the Waterfront, however, this was an error, as the film described was Invisible Enemy (see below) and no other evidence has been found to indicate that Capital Punishment was ever an alternate title for Arson Gang Busters.