There is video of Bush Senior admitting being behind it to anyone who can read people. See his speech on youtube. Where he says something along the lines of crazy lone gunman then laughs his ass off while he looks at an accomplice in the audience. I think it was at a funeral which makes him laughing his ass off even more out of place. Pretty sure he was with the CIA at the time.

Kennedy wanted the US to have green backs instead of pulled out the ass money. So the international bankers had him go away.