In 1950, Douglas played Rick Martin in Young Man with a Horn, based on a novel of the same name by Dorothy Baker inspired by the life of Bix Beiderbecke, the jazz cornetist. Composer-pianist Hoagy Carmichael, playing the sidekick role, added realism to the film and gave Douglas insight into the role, being a friend of the real Beiderbecke. Doris Day starred as Jo, a young woman who was infatuated with the struggling jazz musician. This was strikingly opposite of the real-life account in Doris Day's autobiography, which described Douglas as "civil but self-centered" and the film as "utterly joyless". During filming, bit actress Jean Spangler disappeared and her case remains unsolved. On October 9, 1949, Spangler's purse was found near the Fern Dell entrance to Griffith Park in Los Angeles. There was an unfinished note in the purse addressed to a "Kirk," which read: "Can't wait any longer, Going to see Dr. Scott. It will work best this way while mother is away". Douglas, married at the time, called the police and told them he was not the Kirk mentioned in the note. When interviewed via telephone by the head of the investigating team, Douglas stated that he had "talked and kidded with her a bit" on set, but that he had never been out with her.  Spangler's girlfriends told police that she was three months pregnant when she disappeared and that she had talked about having an abortion, which was illegal at that time.