Details have been released about some of the Americans who died in the U.S. consultate in Libya

Details began to emerge Thursday about some of the three Americans who died in the U.S. consulate in Benghazi with Ambassador Chris Stevens, among them an avid gamer with an extensive online following and a former Navy SEAL who opposed religious fundamentalism in the military.

Glen Doherty was a former Navy SEAL, a pilot who held multi-engine and commercial ratings and a onetime triathlete and ski pro. He left the Navy in 2005 and worked as a "security and intelligence specialist" for the U.S. government, and co-authored a 2010 book, "The 21st-Century Sniper: A Complete Practical Guide," with a former comrade.

He was one of two security officers killed in the Tuesday night assault on the consulate, along with State Department computer expert Sean Smith and Stevens. The other security officer had not been publicly identified Thursday.

Outside Doherty's family home in Woburn, Massachusetts, near Boston, his sister remembered him as "our American hero."

"Glen lived his life to the fullest," Katie Quigley told reporters. "He was my brother, but if you ask his friends, he was their brother as well."

Doherty graduated from high school in neighboring Winchester in 1988, where flags were displayed at a half-staff on Thursday. He played on the varsity tennis and wrestling teams, school officials said in an announcement marking his death. His junior-year English teacher, Judy Hession, recalled him as being "bursting with life."

"Every day his huge smile and his happy-go-lucky optimism filled my classroom," Hession said in a statement released by the school district. "He got along with all types of people, was a class leader and, from the perspective of 30 years of teaching, one of my most memorable students."

He also sat on the advisory board of the Military Religious Freedom Foundation, a group that has battled religious intolerance in the U.S. armed forces. Its leader, former Air Force officer Michael "Mikey" Weinstein, said he was "in a state of shock" after learning of Doherty's death late Wednesday.

"He was one of our most active advisory board members," Weinstein said. "I was surprised he was willing to come on and lend the gravitas that comes with being a Navy SEAL to our cause." Doherty's involvement "made it easier for others to come to us," Weinstein added.

He said Doherty believed the kind of violent jihadists American troops faced were "a very small percentage of the overall mosaic of the Muslim faith," and saw anti-Muslim sentiment in the United States and in the ranks as something that hurt U.S. national security.

"He went back to the Middle East because he cared deeply about the Muslim people, and because he cared about bringing freedom and democracy and human rights to the Middle East," Weinstein said. Doherty "was a kind and caring person, and I'm sure that he gave every last bit of his courage and strength" to defend the consulate and Stevens, he added.

"All this is going to do is light a further fire under us in Glen's name and memory to continue to fight for religious freedom and respect and tolerance."

Secretary of State Hillary Clinton eulogized Smith as a 10-year veteran of the U.S. diplomatic agency, a Foreign Service information management officer who had served in Iraq, South Africa, Canada and the Netherlands.

In real life, he had a wife and two children. But in the virtual universe of the computer game EVE Online, Smith was "Vile Rat" -- one of the leaders of a gamer's alliance of renowned for his diplomatic skill in the multi-player space warfare simulation.

"If you play this stupid game, you may not realize it, but you play in a galaxy created in large part by Vile Rat's talent as a diplomat. No one focused as relentlessly on using diplomacy as a strategic tool as VR," Smith's friend Alex Gianturco wrote in a tribute posted on his website.

Gianturco wrote that Smith had been under fire before, while posted to Baghdad. He usually broke off his messaging, "we'd freak out and he'd come back OK after a bit." But Tuesday night, after reporting "GUNFIRE," Smith "disconnected and never returned," Gianturco wrote.

A few hours earlier, Smith had posted, "assuming we don't die tonight. We saw one of our 'police' that guard the compound taking pictures," he recounted.

"I'm clearly in shock as I write this as everything is buzzing around my head funnily and I feel kind of dead inside," Gianturco wrote.

The identity of the third American killed in the Benghazi attack had not been disclosed Thursday evening, but senior administration officials said Wednesday that the victim was one of two security officers killed.