Howard Green Duff (November 24, 1913 – July 8, 1990) was an American actor. Duff's most memorable radio role was as Dashiell Hammett's private eye Sam Spade in The Adventures of Sam Spade (1946–1950). Due to accusations of Duff being a communist and with his TV and film career starting to take hold, he ultimately left the program in 1950 at the start of its final season; Stephen Dunne took over the voice role of Spade