I can only say this... A man in that mental capacity is at the utmost degree of lack of emotion or empathy. Pure and simple he's quite what he is a rapist. However... Seeing as he had a background I believe he's a desperate and severely violent man. It would make no difference either way if the woman allowed or didn't, this crime seems to be a no brainier to a DA. I'm pretty sure whatever done to him in prison would be no bother to him at all. Since many convicted felons who are in psychiatric care tend to have the tendency to keep smiling that they did it. Most people like that are quite proud of themselves... Which leaves the question why? Well if Religious, some say Satan, if not some say Universe... However seeing as it is and I dearly pray for the little girl. There's great evil and there's really nothing we can do about it. Killing him wont bring her back and I'm afraid if she was, the serious traumatic experiences may leave her scarred or never trust men again. Which is common in most rape cases. So most tend to say death penalty, torture, let him get what he had...
No to all 3 I say... for the correct way this man should not be treated with what he doesnt expect... He knows all the things will happen. He rejoices for it... I say the proper way to make a man like him go... And I mean die. Yes die. Is to simply lock him up, and let him scrounge for food and water. Cut the ties he's looking for, the things he actually needs... He expects a last dinner for death penalty, he expects to eat something during torture and a drop the soap moment. What he doesn't expect is not to feed. Ever seen what a man does to stay alive from hunger? Well he's looking at himself if he's denied nourishment.
Besides I find the whole bit of seeing a man die in RUNNING MAN too Roman fyi.