I hate 9/11 conspiracy theories. There, I said it.
This YouTube video (the first of 5) is a debate between the creators of Loose Change, a popular movie that lays out theories of how the government actually orchestrated 9/11, and the editors of Popular Mechanics, who wrote a book debunking most of the 9/11 conspiracies.
Notice how upset the Loose Change guys get during the debat. They call the other guys liars and get furious at the "lies." Compare that with how calm the Mechanical Engineering remain. The conspirators are making a good living off perpetuatiing the theory. They're on TV and people know how they are. They have every reason to keep these conspiracies alive. The Mechanical Engineering guys are on the other end. Their lively doesn't depend on these theories and go on this no-budget-no-audience show just to prove these guys wrong.
It' OK to ask questions, but in asking those questions you have to look for the answers. Speculation does not belong in "investigative Journalism."