Depends on weather you're making a villain who realises they are evil. Most people don't think of themselves as evil. Hitler and Stalin for example almost certainly thought they the good guys. And truly evil people are very uncommon; Most people don't wake up and want to murder and rape and destroy the world.
They may be well intentioned extremists, who are doing horrible shit because they truly believe that it will create a better world in the long term. After all, if a few million people have to die to create a utopia, isn't it worth it? Every great empire needs to crack a few skulls to establish himself,
Maybe the reason they are trying to rob fort Knox is because someone close to them needs an expensive surgery to save their life and its the only way they think they can raise the money in time. Sure, eventually they'll be caught but its not as though the doctors are going to undo the surgery just because it turns out the money was stolen. He realises what he's doing is wrong, but he'd rather save the life of someone he loves.
"I was tortured" doesn't really work simply because generally people know their torturer and simply want revenge on that person. It doesn't make them evil. But if there is a general target, for instance, a Germanic Warlord who returned to find that the romans had slaughtered his people and enslaved his wife and children. He doesn't know who ordered it, only that it was Rome. So he takes up arms and leads an army to destroy rome, sacking his way across Gaul and Italy to get there. In his eyes, he's the good guy out to destroy those who wronged his people, in the eyes of the people he ironically wrongs in sacking his way across the lands, he is a monster responsible for unspeakable atrocities.
Perhaps he's a crusader; The leader of his faith has declared that god wants them to retake a holy city and slaughter the infidels that have stolen it. As far as he's concerned, he's the good guy whose doing the will of an almighty benevolent being.
Or maybe he's just ambitious and ruthless, coveting a station above his own and willing to stab people in the back and blackmail his way to the top.
Perhaps he views his countries leadership as weak and feels their going to lead only to ruin, so he leads a coup in order to install a better leader (which doesn't even need to be him) who will be able to keep the country stable and perhaps even improve it.
As for not going towards redemption, well, if the person thinks their the good guy then anyone trying to turn them toward redemption is, to them, a liar trying to convince them to become evil.