In Chapters: 2 and 3, when the car plunges down into the elevator shaft, this scene is used again in The Mysterious Mr. M (1946), Chapters: 2 and 3. This scene is originally from Republic's Dick Tracy Returns (1938). Universal purchased this footage and used it in several of its serials.
Based on a real radio show in which unsolved crimes were reenacted in the hope of catching the criminals. However, the only thing this serial took from the "Gang Busters" radio show was the call signal and the title; the story was both an original one and completely fictional.
CHAPTER TITLES: 1. The League of Murdered Men, 2. The Death Plunge, 3. Murder Blockade, 4. Hangman's Noose, 5. Man Under Cover, 6. Under Crumbling Walls, 7. The Water Trap, 8. Murder By Proxy, 9. Gang Bait, 10., Mob Vengeance, 11. Wanted At Headquarters, 12. The Long Chance, 13. Law and Order.
The Main Title and Next Chapter announcer is Hugh Beaumont. In addition, his voice is heard in Chapter 3 as a police dispatcher (scene in Chief's outer office).
The grounding of civilian aircraft in Southern California with the onset of World War II created problems for the crew of the film when they were ordered not to continue shooting scenes at the old Union Airport, then known as the Lockheed Air Terminal, in Burbank. They were forced to dismantle their plane, load it on a truck and move it to Metropolitan Airport at Van Nuys to complete shooting. Daylight airport scenes for Casablanca (1942) would be filmed at Metropolitan Airport a few months later.