Early in the morning of September 12, officials identified five Arab men as suspects in the crashes. The FBI had been able to determine who the suspected hijackers were so quickly because of phone calls from passengers and flight attendants aboard the doomed airplanes. Several people had used their cell phones to alert the authorities that the planes had been hijacked and to inform them of the hijackers' seat numbers. In addition, a tip from a man who had had a confrontation with another driver in the parking garage of Boston's Logan Airport led authorities to one of the hijackers' cars. Inside the car they found flight-training manuals written in Arabic and a ramp pass that allowed access to restricted areas of the airport. By the end of the week, the FBI had identified nineteen hijackers and a man whom authorities suspected was...