If they were really insane then why did they think to use insanity as a defense

I am not denying that someone could have done something while insane and then become sane later

But the burden of proof required shpuld be higher in cases where they conveniently realise they are insane immediately after a crime

As opposed to being so insane tney did not even realize a crime occured

Someone not trying to hide evidence of a crime has been considered more likely to be insane in past precedent