Hijacking airplanes and plunging to one's death is not exactly high tech. But the FBI soon learned that the dead hijackers had been as sophisticated as KGB officers at concealing their activities. They used phony names and public libraries for communicating on the Internet. They used couriers and codes embedded in graphics to convey their messages, a system called steganography. They listed Mail Boxes outlets as home addresses and transferred money through an ancient secret system called hawala, which relies on trust to move sums around the world.
"To me, they acted like normal human beings, nothing abnormal," said Henry George, a flight instructor who taught Atta and another hijacker to fly. "They were polite, maybe even shy."
To finance the plot, the hijackers used at least $500,000 funneled by Mustafa Ahmed al-Hawsawi, a fugitive believed to be al-Qaeda's finance chief. At least $325,000 of the money was disbursed through ATMs, money orders, and credit cards, the rest in cash. Al-Qaeda operatives hatched the plot in Germany with connections in France, Britain, Spain, the Netherlands, Italy, Bosnia, and the Czech Republic.
Most important, to avoid detection, each group or cell targeting a plane kept itself totally separate from the others. As specified in an al- Qaeda training manual, the hijackers themselves did not go to mosques or see other Muslims. Some of them even drank alcohol, which was forbidden by Islam.
"There was no information about them before the attacks," Mawn said. "I'm still shocked and amazed it happened here. These people didn't necessarily bring attention to themselves. All but one was here legitimately. They were not involved in criminal activities. They were separate and unaware of each other until the end."
L ooking back, the one hope of foiling the plot might have been determining what Zacarias Moussaoui was up to when he was taking lessons at the Pan Am Flight Academy in Eagan, Minnesota. On August 15, 2001, an official of the school called the FBI and reported that Moussaoui, a thirty-three-year-old French national of Moroccan descent, wanted to concentrate on navigation and midair turns, not landings or takeoffs. He lacked flight skills and was belligerent and evasive about his background. He paid $6,800 of the $8,300 fee in cash. The biggest plane he had ever flown was a single-engine Cessna, and then only with an instructor. Yet he wanted to learn to fly "one of these Big Bird," as he put it in an E-mail to the flight school — a Boeing 747-400 or Airbus A-300.
Minneapolis was not exactly a hotbed of terrorists. To Dave Rapp, the Minneapolis counterterrorism agent who got the case, this was like Watergate to Bob Woodward and Carl Bernstein. The agent pursued it as if it were the threat it turned out to be.
During an interview at FBI headquarters, I saw the agent's original classified report sitting on the desk of an FBI official. It was a foot high and included a four-inch stack of printouts of the contents of Moussaoui's computer obtained after the attacks.