September 11 hijackers 'cleared by security'
Surveillance video from Washington Dulles International Airport the morning of September 11, 2001, shows four of the five hijackers being pulled aside to undergo additional scrutiny after setting off metal detectors – but then permitted to board the fateful flight that crashed into the Pentagon.
The video shows an airport security guard hand-checking the baggage of one hijacker, Nawaf al-Hazmi, for traces of explosives before letting him continue onto American Airlines Flight 77 with his brother, Salem, a fellow hijacker.
