Alfredo Guerrero sits in front of the Defense Threat

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)