The wife of Robert Bales, the U.S. soldier charged in the shooting deaths of 17 civilians in Afghanistan, says he could not have committed the crimes.

"I don't think anything will really change my mind in believing that he did not do this," Kari Bales told NBC's "Today" show in an exclusive interview. "This is not what it appears to be.''

The 38-year-old Army staff sergeant and father of two from Bellevue, Wash., was charged Friday with 17 counts of premeditated murder in the March 11 killings of civilians in two southern Afghanistan villages. Officials charge he had returned to his base, killed some of the civilians, then left again and killed more.

He is alleged to have fatally shot the civilians, including nine children and four women, while they slept in their beds.

But his wife expressed disbelief, saying her husband, whom she calls her best friend and a "big kid" himself, loves his children and could not have killed somebody else's.

"It's unbelievable to me,'' she said. "He loves children and would not do that. It's heartbreaking."

She said she has spoken to her husband since the killings but not about the allegations. She said she knew their phone conversation was monitored.

"I just don't think he was involved,'' his wife said. "I don't know enough information. This is not him. It's not him."

Before being sent to Afghanistan in December, Bales had done three tours of duty in Iraq. His wife said she was unaware of any clear signs of post-traumatic stress disorder or a traumatic brain injury Bales is reported to have sustained.

"He shielded me from a lot of what he went through,'' she said. "He's a very tough guy. I don't know a lot about the symptoms of PTSD, so I wouldn't know. He doesn't have nightmares.''