I've done a bunch of reseach on both JFK and 9/11. In both cases I can't say who did it for sure, but in latter case I can say the official government story is definitely bullshit, and in the former most very, very likely bullshit.

With modern technology we can see that the government changed evidence to lie about the JFK assassination. As a trained and experienece engineer (30+ years) I know that the scenario posited by the gov't as to how 2 planes knocked down 3 buildings is bullshit. Meaning that people in the gov't got together and decided to lie to the US public. That is a conspiracy.