CIA, LBJ, the Mob, all had a part in it.
Bingo!!! You get the door prize for most correct answer!
Also, JFK was actively seeking answers to the alien situation, Area 51 (which he had been denied access after many attempts to visit there) and other underground facilities and bases being built with CIA drug funds and fake NASA activity funds.
JFK was a true-blue grass roots president working for America's interests, and he was probably the last of his kind.
He was a threat to the money machine that still goes on today.