He’s speaking out. Scott Peterson has been on death row since in 2005, shortly after he was found guilty of murdering not only his wife, Laci, but also their unborn son, Conner. And now — 15 years after Laci and her child were senselessly murdered — he’s sharing what it was like to learn he had been convicted.

Ahead of A&E’s six-part special, The Murder of Laci Peterson, a clip has been revealed of a phone call that he made while behind bars to his sister-in-law Janey; during their call, he describes what it was like to learn that he had been found guilty of murdering his wife and unborn son.

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“It was just like this amazing, horrible, physical reaction that I had,” he says of hearing he was convicted of first- and second-degree murder. “I couldn’t feel my feet on the floor. I couldn’t feel the chair I was sitting in. My vision was even a little blurry. And I just had this weird sensation that I was falling forward — and forward and down and there was going to be no end to this falling forward and down, like there was no floor to land on. I, I was staggered by it. I had no idea it was coming.”

EXCLUSIVE: Scott Peterson Describes Life With Laci in Chilling Prison Letters

The phone call marks the convict’s first public statements about the horrifying case in more than 10 years. In 2012, Scott’s lawyer filed an appeal of his sentence, arguing that the jury was affected by the widespread coverage of the case and that the evidence was insufficient. The court must respond to the appeal by the end of this calendar year, otherwise he is slated to be executed by 2021.

While Scott’s mother, who died in 2013, always maintained her son’s innocence, even his sister and close confidante Anne Bird believed he was guilty of killing his wife. She told Matt Lauer in 2005, “I just know that he did this. It’s very hard to comprehend. And it hurts.”

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