The Whistler. Episode 16, Avarice. John has a big gambling debt but his rich wife won’t give him any money. Oh well, a bowl of arsenic laced ice cream might help. But this is old time radio and surprise endings are the order of the day. (November 29, 1942.)
Inner Sanctum. Episode 30, Death Across The Board. A man purchases a chess set and finds that when played, the winner lives and the loser dies. (June 5, 1945.)