“Nine of the 19 hijackers would have their bags subjected to close scrutiny that morning [September 11, 2001]–six of them because a computerized screening system singled them out for enhanced security checks, and three others because of irregularities in the identification documents that two of them held. Their knives, if discovered, had blades less than four inches long, which meant they were legal.”
– John Miller, Michael Stone, and Chris Mitchell, The Cell, Page 312