The Girl from San Lorenzo (1950)

Two men dressed as Cisco and Pancho have been committing murder and robberies. With a reward now posted the real Cisco and Pancho are captured. But the outlaws have one big final job to do and need Cisco and Pancho as alibis. So they break them out of jail and make them prisoners. This gives Cisco and Pancho a chance to escape and clear themselves by bringing in the imposters.