Michael Tuohey, a ticket agent who checked in two of the 9/11 hijackers at Portland International Jetport in Maine, has admitted he "didn't listen to his gut" despite finding their behaviour suspicious before the attacks. Tuohey, now 80, helped Mohamed Atta and Abdul Aziz al Omari make a connecting flight to Boston, from where they later hijacked an aircraft that struck the North Tower of the World Trade Center. He says he has been haunted ever since by the thought that he might have prevented the atrocity had he acted on his instincts.

Tuohey recalled the pair arriving just half an hour before departure, appearing confused, and Atta becoming rude and impatient as his documents were checked. Despite thinking "if anyone looked like a terrorist, he was a terrorist," Tuohey said he held back because of laws against racial profiling, and only realised the significance of the encounter after watching the attacks unfold on television and being reminded by a colleague that he had checked the men in.