The Adventures of Sam Spade was a suspense/detective radio show starring Howard Duff (in the colorful title role along with Lurene Tuttle as his secretary Effie.  It was based on the private detective character created by Dashiell Hammett, well-known from the book and movie The Maltese Falcon.  The show ran from 1946 to 1951.  Duff was replaced by Steve Dunne in later episodes.The Biddle Riddle Caper:  Sam is hired by a radio producer to help solve a three-year-old-murder. He finds a reel of recording tape disguised as a typewriter ribbon and exposes the murder with the recording. Originally aired January 5th, 1951.Support the show