Transcript for Man who killed pregnant wife, 2 daughters: 'I had no control over it'
We turn next tonight here to a chilling piece of audio, never heard before. Newly released recordings of Chris Watts being interrogated. He's the father who murdered his own wife and girls. And tonight, it is impossible to imagine how any father could share what he did about what his little girl said. Here's ABC's Clayton Sandell. Reporter: It's a dark and disturbing dive into the mind of triple murderer Chris Watts, heard in a newly-released interview with investigators. None of this makes sense. That's why I know you guys keep asking these questions, because it doesn't make sense to me. Reporter: His wife shanann, 15 weeks pregnant, seen here coming home from a business trip in August. Watts says they argued, she accused him of cheating, and told him this -- You're never going to see the kids again. You're never going to see them again. Get off me. Don't hurt the baby. Reporter: Watts says that triggered him into a rage. He says shanann did not fight back as he strangled her to death. It just felt like there was already something in my mind that was implanted that I was going to do it, and when I woke up that morning it was going to happen, and I had no control over it. Reporter: The couple's daughters, Watts says, woke up to see their mother face down in bed, wrapped in a sheet. Is that what happened? Bella came in? What did she say? Something's wrong with mommy. Reporter: Watts says he drove his wife's body from their Frederick, Colorado, home to a remote oil field, his girls in the back seat. There, Watts says he strangled 3-year-old Celeste and 4-year-old Bella. She said "What happened to cece? Is the exact same thing that happened to me as cece?" It's that soft voice she always had -- Reporter: Watts tells investigators he knew his TV interviews a day later were unconvincing. Shanann, Bella, Celeste -- if you're out there just come back. Some people said I just made it look even worse. Reporter: Watts plead guilty, he says, to give shanann's family closure, but he also avoided the death penalty. He'll spend the rest of his life in a prison cell, where he says he keeps a picture of his wife and daughters on the wall. David? Just an awful story. All right, Clayton Sandell Clayton, thank you.
This transcript has been automatically generated and may not be 100% accurate.