Anyone know what song this is?

This question is addressed to anyone who has seen Ken Burns' Huey Long documentary. Near the beginning of the documentary, there is footage of Huey Long's funeral at the Louisiana State Capitol. There is a folksy song playing in the background during this scene. The lyrics go somewhat like this: "Well they shot Huey Long in Louisiana, and he rolled down the Capitol steps...". Does anyone know the name of this song and the artist(s) who performs it? I checked the credits of the film and this song is not listed. If anyone knows, please tell me. Thank you!