The parents of the accused University of Texas stabbing suspect, Kendrex White, are apologizing, offering condolences and trying to understand how their son went from being a student with academic accolades to a suspected killer.

About five weeks before that attack, Kendrex White was in a car crash near the UT campus, according to Kenneth and Shantina White. When police arrived on the scene, he was arrested for DWI.

His parents said he told police he was taking what he described as happy pills. However, his parents think that he may have also hit his head somehow in that crash, causing their son's entire behavior and demeanor to change -- soon before the stabbing.

"Just wasn't himself. You'd ask him a question and the answer was just erratic," Kenneth White said. "There was no reasoning to his answer."

In fact, he had to be involuntarily committed to a psychiatric hospital, where he stayed a little more than a week. Doctors had performed numerous tests on him, including a brain scan. However, medical officials could not settle on an exact diagnosis.

Read More: Sources: UT stabbing linked to mental health, not targeted attack

On the day of the attack on campus, the Whites got a phone call from an attorney representing Kendrix on the DWI charge. The lawyer told them she was looking at photos from the arrest at UT and the man in the photos looked like their son.

"That's when it all started feeling like a nightmare, like 'this is a bad dream, this is not happening," Kenneth said. "I don't know how to put it into words, but this is not the child we know. This not the child we know."

Kenneth and Shantina White, who are both in the military, said they are heartbroken by what happened. They also want to extend their condolences to the family of Harrison Brown, who died after the stabbing, and to the other victims.

"I'm still wrapping my mind around it. It's so surreal like it can't be happening, even though I know it is happening. My heart goes out to all families, all families, involved in this incident and we are so sorry. We didn't see this coming a mile away and we are so sorry," said Shantina White. "I don't know if we missed something, or.. I don't have an excuse. I don't want to make an excuse or make light of anything. but I just know that..."

In the weeks before the attack, the Whites said they would drive from their home in Killeen to UT, where they would routinely check in on their son. They said they had no inkling that he would become violent.

"We did not see this coming at all. We monitored him, we came to visit, we called. We did everything we thought was possible," Kenneth said. "I don't know if we missed something, I don't have an excuse for it."

"Pay attention to your children," Shantina said. "If something don't seem right, if something don't feel right, pay attention."