Rooty Toot Toot (1951)

The story of Frankie and Johnny: Frankie walks into a bar, where she catches her boyfriend Johnny with the sensuous Nelly Bly and kills him in a fit of jealousy. The story is told in song, during the trial, and the bartender and Nelly both tell essentially the same story; Frankie's lawyer spins a wild tale of Johnny out-running bullets and Frankie trying to return his gun, and the jury buys it!
Nominated for the 1952 Academy Award for Animated Short Film.