WELD COUNTY — Hours of interviews and video evidence of Chris Watts show the man who pleaded guilty to murdering his pregnant wife and their two daughters and reveals how investigators learned of his many deceptions.

The evidence also shows how detectives located the girls’ bodies and Shanann Watts’ shallow grave.

9Wants to Know reviewed hundreds of documents including investigative summaries, reports and transcripts, and watched multiple hours of interviews between investigators and Chris Watts that detail how Watts’ story unraveled the more he spoke.

DOCUMENT | Polygraph and Interview with Christopher Watts, 08.15.18

On Aug. 13, Shanann Watts arrived home at about 1:48 a.m. in the morning. Over the next 12 hours, her friends would become concerned about her whereabouts, and ultimately contact police. By 11 a.m. on August 15, Chris Watts agreed to take a polygraph test, during which he would make statements that detectives knew to be false.

“If I ask you on the polygraph test if you physically caused Shanann’s disappearance, can you pass that?” an investigator with the Colorado Bureau of Investigations asked.

Watch the raw footage released by the Weld County DA's office via our YouTube playlist below.

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Watts responded that he could.

“What do you think I mean by that when I ask if you physically caused Shanann’s disappearance?” the detective asked.

“I feel like you’re asking me, ‘did I have anything to do with it myself or did I help somebody do it?’ and I had no part in any of that,” Watts said.

The CBI report said Watts “showed deception” on his polygraph during that line of questioning.

During the polygraph, Watts and the detective discussed the family’s financial problems, and what he described as a marriage falling apart.

During one exchange, Watts said he gently woke up Shanann, and described rubbing her head and her shoulders, before he left for work. He said he told her he wanted to separate.

“It was I just felt like I just don’t feel the connection anymore,” Watts told the detective, talking about what he said was his last conversation with Shanann, in bed on the morning of Aug. 13.

“Was she mad at all?” the detective asked.

“I mean, yeah. I mean she was upset,” Watts said.

“Did she accuse you of anything?” the detective asked

“Being a woman, I mean, she’s like ‘Is there somebody else?’ I’m like no, there’s nobody else,” Watts said. “I believe that she would never have like an affair on me, and she knows that I wouldn’t do that to her.”

By that time, detectives had already determined that Watts was having an affair. Among the hundreds of documents released of the investigation included photos of Watts with a co-worker with whom he was having an intimate relationship.

After the polygraph, detectives told Watts he did not “pass.”

“So now we need to talk about what actually happened,” the detective said.

Another officer would walk in, and Watts asked to talk to his father.

Watts would tell his father he hid the bodies and didn’t know what else to do. He then told detectives that he saw his wife killing his little girls and that he killed Shanann Watts in a rage.

Chris Watts later told detectives where the bodies were hidden at a work site in Weld County and pointed out the locations on a map.

He pleaded guilty to the murders and was sentenced to life in prison without parole on Nov. 19.

PRIOR CHRIS WATTS COVERAGE

Chris Watts case: What we know now and what's next

Timeline: The Chris Watts case

Chris Watts transferred to new facility

Chris Watts' parents question plea deal in murder of wife, daughters

Chris Watts reaches plea deal in deaths of his pregnant wife, two daughters

Warrantless arrest affidavit in Chris Watts case

Childhood friend talks about Shanann and the girls

Colorado mom and husband described as 'perfect couple' ahead of alleged murders

Lengthy documents detail marital problems, affair in Chris Watts murder case

Affidavit: Chris Watts claimed wife killed daughters, then he killed her

Chris Watts’ attorneys accuse DA of leaking information to the press

Court documents: Body of Shanann Watts found in shallow grave

Watch the entirety of our coverage of the Chris Watts case below