On September 14, 2001, Pakistan's Major General Hamid Gul (former Director-General of the infamous ISI security/intelligence service) was reported (in Newsweek) as saying that “Mossad and its American associates are the obvious culprits [for 9/11]”.
One of the main motivating forces for many conspiracy theories is the conspiracist's prior politics. (See this American Thinker article: 'One's Politics Determines One's Conspiracy Theory'. )The theories are usually tailor-made to advance - or gel with - prior ideologies or political beliefs. Thus whatever conspiracy theory a person believes may well be determined almost entirely by his prior politics.