Cowboy from Lonesome River (1944)

Steve Randall heads a group of Mesa Valley ranchers fighting Matt Conroy , who owns the water company and charges exorbitant rates that the ranchers can not afford. Senator Proctor and his secretary, Mona Grant, come from the capitol to inform Randall that a bill is pending to convert Conway's company to a municipal project. Conway imports the Senator's black-sheep look-alike brother, Sheppard Proctor, kills the senator and arranges with Mona, who is in league with him, to have Sheppard pose as his brother. The impostor then proceeds to fight against the bill at the capitol.