He subsequently learned of al-Qaeda and Osama bin Laden , and investigated the 1996 Khobar Towers bombing in Saudi Arabia and the 2000 USS '' Cole '' bombing in Yemen . Partly due to personal friction he had within the FBI and federal government , O'Neill was pushed out of the Bureau in 2001 . He became the head of security at the World Trade Center , where he died at age 49 while helping to evacuate the South Tower during the September 11 , 2001 attacks . O'Neill has been featured in a number of documentaries and books
Khobar Towers bombing
Khobar Towers bombing
John P. O'Neill