I would like to point out that there is a very well documented book out on the subject (has been since 2003) called "Crossing the Rubicon" by Michael Ruppert. It doesn't deal, perhaps wisely, with the physical evidence. However, I would go so far as to say that he proved that
something other than the official version was going on. The most likely explanation, given the evidence he presents, is that a highly placed group in our government learned that the attacks were being planned, contacted the planners, arranged to help them, did so as the attacks were happening, and covered the whole thing up afterward.
Some of the things he points out are:
1) Insider trading in the days leading up to September 11th. Worldwide, it appears that about $2 billion was risked in options trading on the companies whose stock was most likely to be affected by the attacks. The trading patterns were highly irregular--for instance, in the 2 days leading up to 9/11, American Airlines stock showed an increase of 90 times (not 90 percent) the level of put options being written. The only other airline exhibiting a similar pattern was United, the other airline involved in the attacks. Given that both airlines were listed by most major brokerages as good buys, this makes little sense unless those buying the contracts knew about the attacks before hand and knew they would succeed. Unlike with stocks, it's possible to lose all your money in options trading if the stock doesn't go the way you think it will.
Financial institutions and other publicly traded companies with offices in the WTC buildings experienced similar patterns of trading prior to the attacks, whereas
in every case, companies not involved in the attacks had no such similar patterns.
Furthermore, the brokerage that handled the largest volume of the trades in the U.S., A.B. Brown, was formerly run by the number 3 guy at the CIA--Buzzy Krongard.
The Kean commission had the power to subpoena records as to who made those trades, at least in the U.S., but
did not do so. They did make the statement in the record of their proceedings that they thought it was unimportant.
Given the amount of money risked, it's very unlikely that Al-Qaeda would be responsible for it all.
2) There were at least four investigations prior to 9/11 that would have exposed the attacks before they occurred (or at least had the potential to do so). All of them were stopped by a special agent at FBI HQ named Dave Frasca, who shortly after 9/11 was promoted to Deputy Director of the FBI by Bush. The agents who were doing the investigations had all written letters to then director Mueller, who classified them all. The only one he couldn't do that with (because she published it before sending to him) was written by Colleen Rowley. It has been published in its entirety; I strongly suggest reading it. Here's a link to an edited version:
http://www.time.com/time/covers/1101020603/memo.html
Other whistle-blowers have come forward.
3) Related to point 2, we had extensive infiltration of Al Qaeda prior to 9/11. We had seized their assets on multiple occasions. 3 of the hijackers spent a few months
living with an FBI informant who relayed his concerns to FBI HQ. No fewer than 16 foreign countries tried to give us detailed and urgent warnings about the impending attacks, and not only did we ignore them, we rebuffed them. The strangest example seems to have occurred when Malaysian intelligence services tried to give the FBI a taped conversation between two of the hijackers in which they discussed their plans at some length. According to the Malaysian officers (whose names escape me at the moment), they were told that not only were we not interested, further attempts to gather or give us such information might be met with sanctions against their country.
There was an Israeli company called ZIM Israeli Navigation that
broke their lease to get out of the WTC towers 2 weeks prior to the attacks. The Israelis claim to have tried on no fewer than 3 separate occasions to warn us that attacks against the towers were imminent. We didn't listen, so they got their people out.
A CIA field officer named Randy Glass repeatedly faxed letters to the office of Porter Goss (at that time, chair of the Senate Select Committee on intelligence, also recently stepped-down Director of Central Intelligence) warning of imminent attacks in New York City involving hijacked airliners.
The list goes on.
4) Speaking of Porter Goss, the head of the Pakistani intelligence agency, the ISI, was at the time a man named Mahmoud Ahmad. General Ahmad wired $100,000 to Mohammed Atta in May of 2001. On the morning of September 11th, 2001, Mahmoud Ahmad was having breakfast with Porter Goss. Later that week, Condi Rice would deny meeting with him shortly before one of her aides, in a separate interview, embarrassingly confirmed that they had met on September 10th. General Ahmad was one of the men tasked with catching Bin Laden at Tora Bora (anyone else think it's odd that even though we had Bin Laden surrounded at Tora Bora, we pulled our troops back and sent the Pakistanis in?). Of course, Bin Laden escaped.
5) It was reported in the Asian Times, as well as in several European Newspapers, that, while attending a low-level economic summit in Moscow, we announced plans to go to war in Afganistan in October of that year. Those newspapers are extant; if we didn't announce it, it was surely the best bit of journalistic prognostication ever.
6) We were conducting no less than 5 separate exercises that day--at least 3 of which were rescheduled in the months prior to 9/11--that give every appearance of being designed to confuse the air traffic controllers. Two of the exercises involved radar inserts simulating hijacked aircraft, and one involved a live-fly exercise simulating a hijacked aircraft.
In the 8 months prior to 9/11, NORAD scrambled military jets to intercept commercial or private flights that strayed from their registered flight plans no fewer than 41 times, with a mean response time of 7 minutes. However, apparently, on 9/11, we were not capable of scrambling jets for well over an hour and a half. The timeline Ruppert presents, based on statements from official sources, is absolutely compelling. He even shows how the Kean Commission creates a misleading timeline from their own published sources (apparently they thought no one would actually check).
There's plenty more in the book. That said, though, there are parts that wax a little paranoid, so I wouldn't say that I agree with everything in the book. Ruppert's story, if it's true (I have no reason to think it isn't), would probably make anyone's teeth itch if they had lived it, so I don't feel inclined to throw the baby out with the bathwater. But a reasonable person should be able to tell when there's genuine meat on the bone (which is about 90% of the book) and when things need to be taken with a grain of salt.
And, all that said, no, I don't get paid for talking the book up. I don't know Mike Ruppert personally or anything. I just think it's a book that everyone ought to read--any reasonable person couldn't read it and come away thinking there was nothing fishy going on.