In August 1950, "Somebody Knows!", a summer replacement for the CBS program "Suspense" aired a half-hour show on the Black Dahlia killing. It's an extremely rare radio show, but you can listen to a low-fi recording of it here. The program is generally accurate, although there are some errors and the activities of Robert M. "Red" Manley have been judiciously edited. Note that the deadline for the $5,000 prize expired in September 1950.