Rainbow Over the Range (1940)

By the time U.S. Marshal Tex Reed and his pal, Slim Chance, arrive in town , a gang of horse thieves have killed the sheriff and his deputy and have stolen all the horses that Jeff Manners needs to fulfill his contract with the U. S. Cavalry. The gang has control of town politics also, and are about to close the school where Jeff's sister, Mary teaches. Tex tells the mayor, Jim Rader, the school is to be kept open, and when he beats gang member Bart Griffin in a fight, Rader and Griffin decide to get Tex out of the way. They frame Jeff for the murder of Luke Evans and then tell Jeff that Tex is coming to arrest him, hoping that Jeff will kill Tex. When Jeff finds out that Tex knows he has been framed, the two join forces in time to stop another horse raid in which Slim is injured. With the aid of Buck, a gang member befriended by Tex, they get back the original stolen herd and kill or jail the gang members.