Behind Two Guns (1924)

Medicine man Dr. Cutter and his Indian partner arrive in a town where mysterious stage robberies have occurred. Money goes out in a locked strongbox but at the destination the still-locked strongbox is opened and the money is missing, and the stage was not held up. Using binoculars to watch the next stage carrying money, Cutter sees how the money is removed and he and his partner set out to bring in the outlaws and recover the money.