Because there was a preexisting indictment for bin Laden in New York, and al-Mihdhar and al-Hazmi were his associates, the bureau already had the authority to follow the suspects, wiretap their apartment, intercept their communications, clone their computer, investigate their contacts--all the essential steps that might have prevented 9/11. (pg. 330-331)
Soufan wondered why money was leaving Yemen when a major operation was about to take place. Could there be another operation under way that he didn’t know about? Soufan queried the CIA, asking for information about Khallad and whether there might have been an al-Qaeda meeting in the region. The agency did not respond to his clearly stated request. The fact that the CIA withheld information about the mastermind of the Cole bombing and the meeting in Malaysia, when directly asked by the FBI, amounted to obstruction of justice in the death of seventeen American sailors. Much more tragic consequences were on the horizon. (page 329)
Then the CIA chief drew Soufan aside and handed him a manila envelope. Inside were three surveillance photos and a complete report about the Malaysia meeting-the very material Soufan had been asking for, which the CIA had denied him until now. The wall had come down. When Soufan realized that the agency and some people in the bureau had known for more than a year and a half that two of the hijackers were in the country, he ran into the bathroom and retched. (page 362)