"Both of us were just in such a state of trauma," Lyle says in a new interview.
In an interview from behind bars, Lyle said he wasn't "grief-stricken" at all on the line, though he sounded it at the time.
"I think I was just absolutely broken down with stress," he told Keith Morrison. "Both of us were just in such a state of trauma and I just, it just poured through on that call. It made it very easy to make that call, really."
Morrison also asked why they "misled" the police and didn't just tell them what happened.
"I don't think I was going to tell the Beverly Hills Police Department that I killed my parents and here's why and they were going to go, 'Okay, go back home,'" he said with a laugh. "Just self preservation at that point."
After brutally murdering Jose and Kitty Menendez in 1989 with two 12-gauge shotguns, they later testified that their father sexually abused them. Both are currently serving life sentences. Speaking with Morrison (via PEOPLE), Lyle accused the authorities of plotting against them.
"There are, like, 200 to 300 hundred parricide cases a year, where a parent is killed by a child. And they are almost all related to abuse. And they are almost all settled," he told NBC. "This case they picked out as different. And I think that it was very easy, because it was Beverly Hills and my father had a lot of money, to sort of sell this headline that these brothers killed for money."
Erik Menendez is set to break his decade-long silence on the crimes on A&E's "The Menendez Murders: Erik Tells All," airing November 30.
"I'm Erik Menendez. I'm speaking to you from the Donovan Correctional Facility. I'm serving life in prison without the possibility of parole," he's heard saying in a promo for the show. "I've heard many different versions of my life told in the media, and those stories are fictional. I think it's time people hear the truth in my own words without the restrictions of a court room."
"From the moment after, I wanted to go back in time to take everything back that Lyle and I did. It was so wrong," he added. "I didn't want my parents dead, I just wanted the abuse to stop. Years and years of pain exploded that night in an unimaginable violence. It is my own personal hell."