Update: Soldier suspected in attack now in Germany; charges have been filed. (Click here)

ARLINGTON, Va. — As if U.S. warfighters in Iraq don’t face enough stress combating a known enemy in the Iraqi regime, some now might question if the enemy is one of their own, mental experts said.

And that fear of the unknown could be debilitating.

Sgt. Asan Akbar, of the 326th Engineer Battalion of the 101st Airborne, is suspected of throwing grenades into the tent of his leadership on Saturday, killing Army Capt. Christopher Seifert, 27, and injuring 15 others.

(A second serviceman died Tuesday from wounds suffered in the attack. Air Force Maj. Gregory Stone, 40, based in Boise, was pronounced dead at an Army field hospital in Kuwait, the Idaho Air National Guard told The Associated Press.)

Army officials said Akbar, a Muslim, might have acted out of resentment for the U.S.-led strike to topple the Iraqi regime.

Akbar’s mother, Quran Bilal, told The Tennessean in Nashville her son had told her he feared persecution because he is a Muslim, and she said he was not allowed to participate in the first Gulf War because of his religion.

“What goes through a good soldier’s mind is ‘this might not be the only guy,’ and that’s got to be frightening and adds stress to an already stressful situation,” said Scott Swartzwelder, a clinical professor of psychiatry at Duke University in North Carolina. He also works for the Department of Veterans Affairs and counsels patients at the VA hospital in Durham.

Without knowing first-hand details of the incident and ongoing investigation, experts spoke in generalities. But theories abound, from a soldier who snapped under the stress of war to a premeditated terrorist attack, they said.

“This could be a guy with a political or social agenda who decides he’s going to take advantage of his connection to American personnel and American weapons to further his agenda,” said Swartzwelder, who holds a Ph.D. in clinical psychology. “But the first thing that comes to mind is the issue of stress.”

Depression or being “chronically disgruntled,” coupled with placement in a high-stress situation — such as war — “is going to increase the probability that the anger will be unmasked by that stress,” he said.

“The guys [in Kuwait] are under constant stress. They don’t know when the next Scud missile is coming or when the next … terrorist is going to come walking through the gate strapped with explosives.”

Or if they’ll be victims of fratricide.

“Most guys going into combat expect they’re going into harm’s way,” said Dr. Lawson Bernstein, a clinical and forensic neuropsychiatrist, and assistant professor of psychology at the University of Pittsburgh’s School of Medicine.

“But to be fragged in TOC in the rear?” he said of a Vietnam-era phrase that means to be attacked in operational headquarters by someone in your own unit. “This puts the guys at a higher risk for [Post Traumatic Stress Disorder] because it’s such an oddball event.”

The only formal psychiatric evaluation soldiers receive is just before they’re discharged, said Army spokesman Maj. Steve Stover.

“There’s no [psychiatric evaluation] before going off to combat,” he said.

When asked why not, Stover said: “The sheer number of people. We just couldn’t do it.”

However, Army leaders throughout the ranks receive training to recognize signs and triggers of troubled soldiers, he said.

“And you spend a lot of time with the people to your left and to your right,” Stover said. “You’re never going to know for sure how they’ll react until you’re in combat.”

The “Screaming Eagles” of the 101st, based in Fort Campbell, Ky., are continuing with their mission as planned — the best thing for the unit’s morale, the mental health experts said.

And U.S. Central Command has no plans to have warfighters screened for their religious, ethnic or cultural backgrounds before being sent to the combat zone, said Marine Corps Maj. Pete Mitchell, a spokesman in at CENTCOM's forward headquarters in Qatar.

That’s good news for one military legal expert.

“Casting doubt on individual’s loyalty because of ethnicity or religion would work incalculable damage to the cohesiveness of the military as a whole,” said Eugene Fidell, president of National Institute of Military Justice in Washington, D.C. “We are a nation of immigrants, and that would be an appalling development.”

Sign Up for Daily Headlines

Sign-up to receive a daily email of today’s top military news stories from Stars and Stripes and top news outlets from around the world.

Sign up