David Ray Griffin is a professor of theology, a well-respected scholar and author of more than 20 books, including "The 9/11 Commission Report: Omissions and Distortions" and "The New Pearl Harbor: Disturbing Questions About the Bush Administration and 9/11." Griffin maintains that the evidence contradicts the government's official story and that, so far, nobody's come up with a theory that can account for all of the facts.

DAVID RAY GRIFFIN: I simply gather research that has been done by others, a lot of it based on mainline stories from The New York Times, The Boston Globe and The Guardian and so on. These reports tend to, more or less, contradict the official theory.

You say there's reason to question the government's official position on Osama bin Laden.

One problem with the official theory of the attacks being pulled off entirely by the 19 men named as al Qaeda terrorists is that six of them have, subsequently, shown up very much alive. This has been reported in the BBC, but not in the American mainstream press.