Moral Dilemma

If you take out environmental influences from a persons life they aren't the same person, since they only have genetics to operate on. Who you are genetically and who you are environmentally are completely different - and both factor into a human's personality. But what about someone who wakes up from a coma with amnesia? They cannot be the same person they were before, ever again.
Is the new personality truly him or the old personality before the coma?
I answer that both are truly the personalities of that individual. With amnesia you act without the presumptions of years of environment build-up. You act with purity, you act upon your temperament and not your personality.
Temperament : primarily genetic - such as shyness or aggression.
Personality : includes some traits learned or influenced by environment - such as honesty.

So a friend answered that it also depends on whether or not the pt with amnesia will ever remembers himself and his actions. If he remembers himself slowly while he has retrograde amnesia then he could become his old self again. Or would he be able to disregard his past and continue to become the new self he has started?

Ex : Sociopath, grown by his environment (beatings from a father, mothers OD, kids at school ridiculing him and bullying him etc.), kills several people who hurt him, including his father. One day he falls from a serious height and he ends up in a coma, and when he wakes up he doesn't remember anything and no one knows who he is. They give him a new identity. He is pleasant to his nurses, helps old women cross streets, shows up for his new job on time and works hard. He takes pride in gardening and doing cross-word puzzles.
What would happen if he started to remember his childhood? Would he regress to being a sociopath again or feel remorse?
What would his real genetic tendencies be without the taint of a terrible enviornment?
If the police found out who he was and what he's done would they be right to prosecute him for murdering his father and others who hurt him? Even if he isn't at all the same person?

What do you think?