Who is the Afghan rampage shooter?

(CBS/AP) Little is known about the U.S. soldier who gunned down 16 Afghan civilians in a rampage over the weekend and probably changed the outcome of America's 10-year commitment in Afghanistan.

So far, officials have acknowledged he is a 38-year-old staff sergeant who has been in the military for 11 years. He is married with two children. He had previously served three tours in Iraq, and was deployed to Afghanistan on Dec. 3 with the 2nd Battalion, 3rd Infantry Regiment of the 3rd Stryker Brigade, 2nd Infantry Division, based at Joint Base Lewis-McChord located south of Seattle, according to a congressional source, speaking on the condition of anonymity because of the sensitivity of the matter.

He was attached Feb. 1 to the village stability program in Belambai, a half-mile from one of the villages where the attack took place, the source said.

CBS News correspondent David Martin reports he rolled a vehicle in Iraq in 2010, was evaluated for mild traumatic brain injury and later returned to duty. Earlier, he had passed a psychological exam to qualify for sniper school, which, as one officer said, "carries its own psychological baggage depending on how many people you've capped."

His name has not been released and will likely be made public only when he is charged.

The shooter's family family has now been moved onto Joint Base Lewis-McChord for their safety. He was assigned to support a special operations unit of either Green Berets or Navy SEALs engaged in a village stability operation. Special operations troops pair with local residents chosen by village elders to become essentially a sanctioned, armed neighborhood watch.

The soldier, now in U.S. custody, is accused of killing 16 Afghan civilians in their homes in the middle of the night between Saturday and Sunday and then burning some of their corpses. Afghan President Hamid Karzai said nine of those killed were children and three were women.

Fort Lewis has a history of troubles coming from soldiers stationed there, so much so that a few veterans say they are not surprised that the Afghan rampage soldier came from there.

Two U.S. defense officials said an investigation has been started by the Army Criminal Investigation Division, but that it was too soon to say when any charges might be filed.