Signs of Guilt

1. Insider Trading
They don't talk about it on TV anymore, but someone tried to make money with unusual stock trades right before the terrorist attacks of September 11. Who knew to bet that United Airlines would lose money?
Insider Trading before 9-11
2. No flight for public officials on 9/11
Flight Warnings
3. Destruction/removal of evidence
Why was there no forensic examination of the debris from the towers?
Why was there criminal removal of the debris?
4. Seizing and hiding Video Evidence
Why aren't the contents of the 8 black boxes made public?
Where are all the Pentagon surveillance tapes? Why aren't their contents
revealed? Why were surveillance tapes seized from the Hotel and the service station close to the Pentagon?
5. Hesitance in setting up a commission
The National Commission on Terrorist Attacks Upon the United States,
also known as the 9/11 Commission, was set up in late 2002 (over 14 months
after the event) "to prepare a full and complete account of the circumstances
surrounding the September 11, 2001 attacks", including preparedness for
and the immediate response to the attacks.
  Check Wikipedia
6. Little cooperation with Commission
Small budget, limited mandate, witholding evidence, conditional testimony, etc.
Foot Dragging