The Unholy Four

When a violent gang robs a bank, they also commit arson because the diversion eases their getaway. While the local prison is burning, four of its inmates profit from the general turmoil too. Among the four escapees is Chuck Moll, a young man suffering with amnesia, who only remembers about his previous life that he has been home in the town Oxaca. For lack of a better idea all the fugitives go there. 

It shows that Moll is not forgotten in Oxaca. Lion Udo, the father of one of the bankrobbers, recognises Moll. He, whose clan has a feud with Moll's family, takes advantage of his condition by turning him against his own kin. Before this plan works out, Moll is warned on time by one of his fellow fugitives. Moll contacts his half-brother Alan and his father John Caldwell. Only then he learns what caused his amnesia and why he'd ended up in prison. It was Alan who once mistreated Moll and ran a scheme to put him away. He hates Moll since he knows that he is not the son of John Caldwell, but the child of a rapist.