- In August 2001, the CIA briefed President Bush on the possibility that Al Qaeda might use hijacked airliners to win concessions from the US.
- AP reported details from a July 2001 memo of Kenneth Williams, an FBI agent in Phoenix, who presciently noted a pattern of Arab men signing up at flight schools, and recommended an investigation. FBI director Robert Mueller didn’t see the report until after September 11.
- In August 2001, when the US detained Zacarias Moussaoui, now in custody on the charge of complicity in the attacks, the FBI did not inform the White House’s Counter-terrorism Security Group.
- FBI agent Coleen Rowley sent a 13-page letter to Mueller accusing the bureau of deliberately obstructing measures that could have helped disrupt the attacks. She accuses Mueller and others of having "omitted, downplayed, glossed over and or/mischaracterised" her office’s investigation of Moussaoui.
- A recent Newsweek report claims the CIA had been tracking two of the hijackers—Nawaf Alhazmi and Khalid Almihdhar, of the team that crashed into the Pentagon—since January 2000 but failed to alert the Immigration and Naturalisation Service. From the time the CIA identified them as terrorists, the two lived openly in the US, opened bank accounts and enrolled in flight schools. These lapses will now be scrutinised by the joint House and Senate intelligence committees in their hearings in the weeks to come.