What happens
Bruce Wayne, who secretly is Batman, tells his friend Clark Kent that threatening letters and phone calls aimed at Robin have come from Eric Larson, a man who died in prison two weeks earlier. Batman recorded one of the calls and played it to circus people who knew Larson, and both swore the voice was his. Clark and Bruce travel to the state prison to speak with Warden Hobbes, who vouches that Larson died there and was buried in the prison cemetery. Clark asks to see the grave, and the warden agrees to have the bronze casket opened. This is part one of the Superman radio serial The Adventures of Superman, first aired September 26, 1946.
Bruce Wayne's house, then the state prison and its cemetery
Characters: Clark Kent, Bruce Wayne, Batman, Robin, Eric Larson, Warden Hobbes, Jimmy Olsen
Listen for: The bronze casket of Eric Larson is opened in the prison cemetery.
Written from the episode itself; it never gives away the ending. Every recording is remastered for the stream: cleaned of rumble, hiss and mains hum (and the old TV whine where we found it), then levelled in two passes to steady broadcast loudness, so one show is never quieter than the next.