At least 13 people were killed and 30 more wounded in a shooting at Ford Hood in Texas on Thursday, and authorities are piecing together a troubling portrait of the man thought responsible. The Army says the gunman is Major Nidal Malik Hasan, a psychiatrist born in Virginia and raised in the United States. Hasan, who is alive but in a coma and on a ventilator, allegedly shouted "Allahu Akbar!" before starting his shooting rampage, which is Arabic for "God is Great." Hasan, who officials now say acted alone, allegedly carried two weapons, one of them semi-automatic, which explains the high casualty count. The Marine Corps. Times cited a Pentagon source as saying Hasan, 39, is "a psychiatrist recently reassigned from Walter Reed Army Medical Center in Washington, D.C., to work with soldiers at Darnall Army Medical Center on Fort Hood." His cousin said at Walter Reed, Hasan treated soldiers returning from war with combat stress and PTSD and was afraid of his own impending deployment to Afghanistan. Hasan told relatives in Virginia he was having second thoughts about his military career when soldiers teased him for being Muslim, The New York Times reports. Hasan reportedly drew the attention of federal law enforcement six months ago for online posts about suicide bombings and other threats including "a blog that equates suicide bombers with a soldier throwing himself on a grenade to save the lives of his comrades." An imam at a Maryland mosque he attended said that Hasan was a lifelong Muslim, but showed little sign of political or religious zealotry.