I watched an interview with Rubin “Hurricane” Carter on Skavlan, and am deeply impressed. Here is a man filled with anger and innocently convicted, profoundly transformed by his prison experience. He mentioned that he learned how to pray in prison, and that may well be what catalyzed the transformation. The interview starts with a Norwegian introduction, but is then in English.
It is all described in Eye of the Hurricane: My Path from Darkness to Freedom, which is now close to the top of my reading list.