American Killed in Libya Was on Intel Mission to Track Weapons One of the Americans killed alongside Ambassador Christopher Stevens in an attack on a U.S. diplomatic mission in Libya Tuesday told ABC News before his death that he was working with the State Department on an intelligence mission to round up dangerous weapons in the war-torn nation. In an interview with ABC News last month, Glen Doherty, a 42-year-old former Navy SEAL who worked as a contractor with the State Department, said he personally went into the field to track down so-called MANPADS, shoulder-fired surface-to-air missiles, and destroy them. After the fall of dictator Moammar Gadhafi, the State Department launched a mission to round up thousands of MANPADS that may have been looted from military installations across the country. U.S. officials previously told ABC News they were concerned the MANPADS could fall into the hands of terrorists, creating a threat to commercial airliners. READ: Nightmare in Libya: Thousands of Surface-to-Air Missiles Unaccounted For Doherty said that he traveled throughout Libya chasing reports of the weapons and once they were found, his team would destroy them on the spot by bashing them with hammers or repeatedly running them over with their vehicles. When ABC News spoke to Doherty in late August, he was enjoying a short time off in California before heading back to Libya just days ago. The State Department declined to comment on Doherty's involvement in the MANPADS program, but pointed to a previous statement from State Assistant Secretary for Political-Military Affairs Andrew Shapiro in which he said the department was looking at "every possible tool to mitigate the threat." According to military records provided to ABC News, Doherty joined the Navy in 1996 and was a combat medic and a decorated member of the elite SEAL teams by the time he left active duty in 2004. He's described in glowing terms as a top-tier SEAL and better friend in the book "The Red Circle," written by Doherty's longtime friend and SEAL sniper school partner, Brandon Webb. "Glen was a superb and respected operator, a true quiet professional," Webb told ABC News today. Don't feel sorry for him, he wouldn't have it. He died serving with men he respected, protecting the freedoms we enjoy as Americans and doing something he loved. He was my best friend and one of the finest human beings I've ever known. Doherty's mother, Barbara, told ABC News' Boston affiliate WCVB she had been notified of her son's death late Wednesday. "He was the most wonderful person," she said. We are all in pain and suffering. Ambassador Stevens and State Department information management officer Sean Smith were killed in the first wave of attacks in Benghazi when the building they were in was set on fire around 10 p.m. local time Tuesday, a senior administration official told reporters. Doherty was apparently one of two other Americans who were killed in a firefight nearly two hours later, while the facility was still under attack. The fourth victim has not been identified. ABC News' Dana Hughes contributed to this report.