The Blue Beetle began as a comic book in August, 1939. In 1940, CBS radio brought him to the airwaves.
Dan Garrett was a rookie cop who had a good friend named Dr. Franz, who was a pharmacist and an inventor. Dr. Franz invented a lightweight bulletproof "superbeing" costume for Officer Garrett, and he also concocted a special formula called Vitamin 2X, which gave Garrett "super energy."
With the magic vitamin and the bulletproof uniform, Dan Garrett became the Blue Beetle, fighting for truth, justice, and - no, wait, that's the OTHER superhero.
The Blue Beetle reappeared briefly in the 1950s, then again in the 1960s, and finally as a DC property in the 1980s.
And by the way, if you enjoy Nightbeat, you'll be happy to know that the Blue Beetle was played on the radio by Frank Lovejoy.
This episode, Thoroughbreds Always Come Through, aired on June 19,1940.