SEATTLE — In her first media interview, Karilyn Bales — wife of the Army staff sergeant accused of killing 17 Afghan civilians — says it’s hard for her to believe her husband could have committed the killings. She also says she didn’t notice behavior indicating that he could be suffering from post-traumatic stress disorder.

“This is not him. It’s not him,” she told NBC’s “Today” show Monday in an interview near her home in Washington state. She described the 38-year-old soldier as a man who loved children and who wanted to avoid further combat deployments in order to spend more time with his own two kids.

“He’s like a big kid himself,” she said.

Robert Bales, a veteran of three deployments to Iraq, was on his fourth assignment, this time in Afghanistan, when the shootings occurred during the pre-dawn hours of March 11 near a small Army outpost in Kandahar province. Five of the dead were women; nine were children.

Bales said her husband had not appeared to be suffering ill effects from his previous deployments, and had not even mentioned a head injury he suffered in Iraq until he returned.

“Not until he came back and said that he, you know, had been blown up. He shielded me from a lot of what he went through. He’s a very tough guy,” she said. “He kept a lot from me.”

She said Bales never seemed to exhibit classic symptoms of post-traumatic stress disorder, an affliction that haunts many veterans of the wars in Iraq and Afghanistan.

“I don’t know a lot about the symptoms of PTSD, so I wouldn’t know,” she said. “He doesn’t have nightmares, you know, things like that. No dreams.”

Karilyn Bales kept blogs over the past several years that described what looked to be a typical military family life. She cared for their children, ages 3 and 5, and hoped that her sniper-trained husband could get an assignment that would allow him to be home more.

Instead, she got a version of the phone call military spouses dread most.

“I was actually at the grocery store that morning, and (got) a phone call from my parents, and they said, ‘Well, it looks like … some Afghan civilians were killed by a U.S. soldier,’ ” she said. “I saw 38-year-old staff sergeant, and I don’t think there are very many of those, and I probably prayed and prayed that my husband wasn’t involved. And then I received a phone call from the Army saying that they would like to come out and talk to me.”

She was relieved. A phone call meant he wasn’t dead.

“They held my hand and they just said that perhaps, you know, they thought that he had left the base and gone out and perhaps killed the Afghan civilians,” she said. “And that was really the only sentence. And I just started crying.”