At least three eyewitness had spotted al Qaeda terrorists testing the security checkpoints at Boston's Logan Airport in May 2001, four months before the 9/11 attacks.
An American Airlines official, one of the eyewitnesses had confronted the ringleader Mohamed Atta after seeing him videotape and examine a security checkpoint four months before he boarded the airlines' flight that crashed into the World Trade Center.
Brian Sullivan, a former FAA special agent who at the time had warned of holes in security at the airport said that he was convinced that had some action been taken after seeing Atta at Logan, 9/11 attacks could have been avoided.
The three Boston witnesses were interviewed by the FBI. However, there was no mention of them in the 9/11 Commission Report.
According to reports, Atta's bags containing box cutters and mace or pepper spray got past screeners on September 11 , 2001 and he took a seat in business class of American Airlines Flight 11 unimpeded.