The Doolins of Oklahoma (movie, 1949)

When the Daltons are killed at Coffeeville, gang member Bill Doolin arriving late escapes but kills a man. Now wanted for murder, he becomes the leader of the Doolin gang. He eventually leaves the gang and tries to start a new life under a new name. But the old gang members appear and his true identity becomes known. So once again he becomes an outlaw trying to escape from the law. Written by Maurice VanAuken