JUDY WOODRUFF: Much more also emerged today on the accused gunman, Major Nidal Malik Hasan, a native of the Washington, D.C., area.
Ray Suarez reports on that part of the story.
RAY SUAREZ: This mosque in Silver Spring, Maryland, was Hasan’s spiritual home, in the region where he spent much of his young professional life.
Dr. Asif Qadri works at a medical clinic associated with the mosque, and knew Hasan.
DR. ASIF QADRI, Muslim Community Center: And, to me, he was very social, quiet, but, he would not generally go and offer you and engage you in conversation or discussion. And anybody who talked to him was very casual, and he was nice about it.
RAY SUAREZ: The Muslim center is more than 1,000 miles from yesterday’s carnage, and the imam there found it hard to reconcile the man he knew with what he saw yesterday on television.
IMAM: There is no way. That’s why I’m shocked. Man, I’m shocked.
RAY SUAREZ: Today, as the investigation in Texas continued, a key question remained: how this devout man, a psychiatrist responsible for counseling soldiers, could have committed such a crime.
Born in Arlington, Va., and raised by Jordanian immigrant parents, Nidal Malik Hasan enrolled in the Army straight out of high school. The military sent him to college at Virginia Tech, then on to the Uniformed Services University in Bethesda, Md., to study psychiatry.
DR. ASIF QADRI: He was very grateful to the Army, who trained, educated him. You know, he was very grateful, and he was proud.
Experience with PTSD
RAY SUAREZ: For six years, he treated soldiers suffering from post-traumatic stress disorder at Walter Reed Army Medical Center. Each year, service members cycle through Walter Reed with grave physical wounds and profound psychological ones.
But Professor Stevan Hobfoll, a specialist in stress disorders, says practitioners often deal with patients in crisis.
STEVAN HOBFOLL, Rush University Medical Center: There are hundreds, if not thousands, of military psychiatrists, psychologists, social workers. They're -- they're strong, tough, and empathic. They -- they can take this. If anything, it's not that you're not saddened in your work, but you're also strengthened by it, because you know you're helping and doing your part.
RAY SUAREZ: During his years in Bethesda, he lived a quiet life as a single man renting the basement of this house. His upstairs neighbor, who wouldn't come outside, said she hardly knew him, even though she lived just one flight up.
He became increasingly religious after the deaths of his parents, and disenchanted with the military, at one point telling relatives he was anxious to get out, according to his cousin, Nader Hasan.
NADER HASAN: It was the harassment that I think was what got to him, was him being referenced from his Middle Eastern ethnicity, even though he was born and raised here and went to high school here in Northern Virginia.
RAY SUAREZ: The Muslim chaplain at Fort Hood told ABC News that harassment toward Muslim service members was not necessarily widespread at the base.
Backlash against Islam
MAJOR KHALID SHABAZZ, U.S. Army: Time to time, we have a lot of counseling time with the soldiers, and they would complain about being taunted and harassed. Some of it was mild joking and some of it was just misunderstanding. So, statement, it does create a real problem.
RAY SUAREZ: Still, at the Council on American-Islamic Relations, Ibrahim Hooper's BlackBerry has buzzed today with hostile messages, one calling for all-out war on Islam.
IBRAHIM HOOPER, national communications director, Council on American-Islamic Relations: Unfortunately, there's a cottage industry of Muslim- bashers who are already using this tragic incident and exploiting it to further promote interfaith mistrust and hostility, and to create divisions within our society.
And that's why we ask mainstream practitioners of all faiths in America to not allow that to happen, to remain calm, to remain unified in the face of those who would exploit this kind of tragic incident.
In this case, unfortunately, it occurred in America, which makes it even more troubling. And that's why, when we have some kind of incident like this happen, despite our attempts every day to enhance understanding of Islam, and show American Muslims as ordinary citizens that go about their daily lives, it ends up being one step forward and two steps back for our community.
And that's just the -- the facts we have to face in the post-9/11 era.
RAY SUAREZ: Today, Muslim groups roundly condemned the attack. The American Arab Anti-Discrimination Committee called Hasan a 'rogue gunman.'