He built a bunker to keep his captives locked up in. That requires a measure of sanity and planning in order to premeditate and organise. During every step of his evil planned actions he had the choice to stop. He managed to fool all his neighbours, friends and colleagues (if he had them) outside in the real world for years. That also requires some measure of sanity so how would he be insane ? My verdict would be that of 'manipulating psychopath.' I just wonder how the legal system anywhere as it exists currently can provide a deterrent for these people ?