Chris Watts Was 'Cold as Ice' Before Triple Murders — and What Wife's Mom

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Chris Watts Was ‘Cold as Ice’ Before Triple Murders — and What Wife’s Mom Told Her Before She Died

Shanann Watts’ parents knew her marriage was having problems and that her husband of nearly six years, Chris Watts, had grown distant and unloving — but, her mother advised her, give him his space. She had no idea what he would do next.

“She just couldn’t understand why he was so cold,” Shanann’s mom, Sandra Rzucek, explained to ABC News in an episode of 20/20 airing Friday night.

Frank Rzucek, Shanann’s father, joined her in their first-ever interview about the August triple homicide of Shanann and her kids, which attracted international attention.

In an exclusive clip from the sit-down (above), the Rzuceks describe how Shanann, 34, had noticed that Chris, 33, was acting strangely in a way that was difficult to understand.

“Nothing that was really — that I could physically see,” Frank told ABC. “Something wasn’t there, but [it] didn’t click to nobody.”

Sandra said the estrangement seemed to have been going on for a “few weeks, maybe a month.” Chris acted “just cold as ice,” she said, not replying, not responding.

“I just said, ‘Give him space,’ you know,” Sandra recalled. “But little did we know.”

RELATED: Video Shows Chris Watts Lying to Cops After Family Was Reported Missing

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From left: Sandra and Frank Rzucek

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From left: Shanann and Chris Watts

In fact, prosecutors later revealed, Chris had grown infatuated with a co-worker with whom he began an affair that summer before the murders. Motivated by his desire for a “fresh start,” he strangled Shannan at their Frederick, Colorado, home early on Aug. 13 and smothered their daughters, 4-year-old Bella and 3-year-old Celeste. Then he hid their bodies and publicly pleaded for their safe return.

Shanann was 15 weeks pregnant with a son, Niko, when she was killed.

“She was a good soul,” Frank told ABC in a previously released clip from the 20/20 episode.

“She [Shanann] would do anything for her children,” he said. “She just loved her children, and she wanted them to have everything growing up.”

Chris was arrested soon after the murders and confessed to killing his wife — but claimed he did so only after watching her strangle Celeste in apparent retaliation for announcing he wanted to split.

RELATED: Surveillance Footage Shows Chris Watts Loading Truck After Murdering His Family

When in November Chris surprisingly pleaded guilty to all of his charges, to avoid being executed, he confirmed that earlier confession was a lie. He will spend the rest of his life in prison.

“The Rzuceks are utterly devastated,” ABC News’ Amy Robach, who interviewed Frank and Sandra and others for 20/20, tells PEOPLE. “They told me that in one night they lost all their grandchildren and their only daughter, a daughter they video chatted with every single day.”

“However,” Robach continues, “they have a strong faith in God and that, along with their son, is what is getting them through each day. They are speaking out because they want to set the record straight about Shanann.”

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Chris Watts (center) with his daughters

Despite Chris’ admission of guilt and some of the answers that came after, including details about his motive and the mounting marital strife between him and Shanann, authorities have cautioned that such a crime is, by its nature, not completely knowable.

Chris himself has not been required to make a public confession as prosecutors do not believe he would tell the truth.

RELATED: After Killing Pregnant Wife, Chris Watts Claimed Baby She Was Carrying Wasn’t His

“I was just so shocked to hear from every single person we interviewed — close friends, family and co-workers — that there was absolutely no warning sign regarding Chris,” Robach tells PEOPLE. “Everyone told us he was a loving father and husband and an all-around good guy. It became for me the most chilling part of the story. Do you ever really know who you’re married to, do you ever know what someone is capable of?”

20/20 airs Friday (10 p.m. ET) on ABC.