Behind the High Wall (1956)

A group of convicts break out of prison, killing a guard, kidnapping the warden and forcing a reluctant inmate to accompany them. However, when a car accident kills everyone except the warden and the inmate hostage, the warden steals $100,000 of the gang's money, then when police arrive he accuses the inmate of the guard's murder in order to cover up his own crime.