A person can be judged insane, but guilty. Do you think Hitler Y”Sh was a SANE man, or Saddam Hussein, or David Berkowitz? I am sorry that people have this type of mental illness, but they are still guilty of horrific crimes and cannot get away with them because they are crazy.
Clearly Levi Aron knew what he was doing when he kidnaped Leiby and shlepped him to a wedding in Monsey. He further had enough wits about him to PANIC when he realized how many people were searching for the boy, and commit an act of violence that stuns the world, not just the Jewish community. I am sorry for his family, who will forever live with the knowledge of their raising such a twisted monster.