He did go through a physiological test and the report says he is sane and do not qualify the definition of psychological ill, but then the report says in the next meaning he is a psychopath with narcissistic behavior, pathological lies and with a severe sexual deviation.

Trying to understand why a sane person would commit such crime is impossible, so I personally consider that what we have heard and seen is not the behavior of a sane person. Trying to frame it like a video game is trying to impose rules of sanity to explain insanity.