Twenty years after his younger sister, JonBenet Ramsey, was murdered in their home, Burke Ramsey breaks his silence about the cold case that continues to grip the nation. Now 29 years old, Burke gives his first-ever interview to Dr. Phil about what he knows about the murder and why he decided to speak out now.

The three-part interview begins Monday -- watch more here.

Asked about the theory that their mother killed JonBenet in a fit of rage, Burke responds, "I've never seen her get in a fit of rage. I mean, it doesn't make sense not to say she never got upset, but nothing near like laying a finger on us, you know, let alone killing her child."

WATCH: JonBenet Ramsey’s Brother: ‘You’ve Got To Stop Crying At Some Point’

Dr. Phil asks, "She wasn't into corporal punishment? She didn't spank you?"

Burke responds, "No, we didn't get spanked. Nothing of the sort; not even close."

Watch the video above to see what happened when Burke, at age 9, was interviewed by a psychologist, who asked him to draw a picture of his family.

"Did you consciously not draw JonBenet?" Dr. Phil asks.

"I don’t really know what was going through my head, but she was gone, so I didn’t draw her," Burke responds.

WATCH: JonBenet Ramsey’s Brother On Why He Stayed In His Bedroom After Hearing His Sister Was Missing

See more from these secret interrogation videos during Burke’s exclusive interview with Dr. Phil starting Monday, September 12 on the season premiere of Dr. Phil. Check here to see where you can watch.