JIM LEHRER: And now how the Fort Hood community is coping.
"NewsHour" correspondent Tom Bearden was in Texas over the weekend, and he filed this story.
TOM BEARDEN: On Sunday, in churches all over this area, people mourned the tragedy at Fort Hood. Local ministers in Killeen, the community that surrounds Fort Hood's main gate, organized a joint memorial service at the First Baptist Church last night.
The governor was there. So was State Representative Jimmie Don Aycock.
STATE REP. JIMMIE DON AYCOCK, R-Texas: In Killeen, our unique purpose and focus is to take care of our soldiers. There have been other acts of violence in our community that we don't understand, but this one was different, because the man with the pistol wore that uniform.
TOM BEARDEN: More than a few of the soldiers who spend time at Fort Hood come back to this area and retire once their military careers are over.
One of them got elected mayor of the town of Killeen. Former Sergeant Tim Hancock says people here were shocked by the shootings. But he adds, this town has had a lot of experience dealing with tragedy.
TIMOTHY HANCOCK, mayor, Killeen, Texas: Every week or so, we get returning, and we have memorials for soldiers that were killed in war. So, that -- you know, we're cognizant of it. We know what it is like.
TOM BEARDEN: The mayor says, like everybody else, he wants to know why Major Hasan attacked the troops he was supposed to care for.
TIMOTHY HANCOCK: I'm glad that he's still alive, and I'm glad I think that he's alive, because I think that this will give us an opportunity to find out -- a better chance of finding out why these things happen.
TOM BEARDEN: Just down the block from city hall, there's a coffee shop called Under the Hood. A lot of troubled soldiers come here, and it's also frequented by peace activists.
One of the shop's frequent customers, PFC Michael Kern, has his own idea about why Hasan started shooting. Currently transitioning out of the Army on a medical discharge, he had a nodding acquaintance with Major Hasan, who was a psychologist in the unit where he's being treated.
PFC. MICHAEL KERN, U.S. Army: Seemed like a total normal guy to me. I mean, even some of the patients that I have talked to that were his patients didn't seem any -- you know, couldn't really tell anything about him. You know, he just seemed like a normal guy.
TOM BEARDEN: Kern thinks Hasan's own mental health was likely affected by the stress of years of treating deeply disturbed soldiers.
PFC. MICHAEL KERN: OK, he's there to help the soldiers. Who is going to -- you know, we're giving him so much. We're telling him so many war stories and, you know, telling him all the bad things that we have done and all the bad things that we have been through. Who's going to help him when he's having the same problems thinking about all the things that's going on in Iraq?
If I'm going to sit here and I'm going to tell you, look, I murdered this person, you know, I got blown up, I lost -- my friend died in my arms, and then I'm going to tell you you're going to go to Afghanistan, you're going to have some hesitant thoughts, too.
Charles Luther has been counseling Kern on his effort to leave the service. He's a former Army sergeant who suffers from post-traumatic stress disorder. He spends most of his free time advocating for better mental health care for disturbed soldiers.
He thinks because the shooter was a Muslim, other Muslim soldiers will face a backlash from already troubled non-Muslims within the ranks.