Sunset on the Desert (1942)

Judge Kirby is being blackmailed and forced to let outlaws go free. He was once the partner of Roy's father and when Roy reads in the paper that he is in trouble he heads out to help him. Arriving, Roy quickly realizes he has been mistaken for one of the outlaws and is not wanted in town. However he stays, and now posing as that outlaw, hopes to learn who is causing all the problems.