Alfredo Guerrero sits in front of the Defense Threat Reduction Agency building at Fort Belvoir, Va., on June 10, 2016, where he works as the anti-terrorism program manager. Guerrero was on top of Bldg. 131 of the Khobar Towers complex in Dharan, Saudi Arabia, on June 25, 1996, when he spotted a suspicious large gas truck drive toward the building. When the truck parked and two men jumped out and got into a car that had been following them, Guerrero and two other Airmen immediately began evacuating the building. A short time later the truck exploded, killing 19 Airmen and injuring more than 350 people. (U.S. Air Force photo/Staff Sgt. Christopher Gross)