KUSA — A plea deal has been reached in the case of Chris Watts, the Frederick man accused of killing his pregnant wife and two young daughters earlier this year.

Watts pleaded guilty to all nine counts relating to the murder of his wife Shanann Watts and daughters Bella, 4, and Celeste, 3, during a court appearance on Tuesday afternoon.

Watts had claimed that he killed his pregnant wife in “a rage” after he realized that she had strangled their two daughters – a shocking assertion outlined in court documents.

But Weld County District Attorney Michael Rourke made it clear he didn’t believe Watts, charging the man with multiple felony counts alleging that he was the one who killed his wife of nearly six years.

Watts originally faced the death penalty or life in prison without parole. Under the plea deal, District Attorney Rourke eliminated the death penalty from consideration. Watts now faces a minimum of four life sentences with no possibility of parole.

Court documents revealed, among other things, that detectives concluded that Chris Watts was “actively involved in an affair with a co-worker.”

Watts, according to an arrest affidavit, denied it.

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Watts told investigators that he had told Shanann Watts that he wanted to separate, according to the affidavit. He said he walked downstairs for a moment, then returned to talk to Shanann again, according to the affidavit.

After returning to the couple’s bedroom, he told police that he looked at a baby monitor he saw Bella “‘sprawled’ out on her bed and blue and Shanann actively strangling Celeste,” a detective wrote in the affidavit.

“Chris said he went into a rage and ultimately strangled Shanann to death,” the affidavit said.

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Watts was charged with nine felony counts:

- Five counts of first-degree murder. Three of the counts allege that he killed his wife and each of his daughters after deliberation. The other two counts allege that he killed each of his daughters, that each was under the age of 12, and that Chris Watts was in a position of trust.

- One count of unlawful termination of pregnancy. That count alleges that in killing Shanann Watts he ended her pregnancy.

- Three counts of tampering with a deceased human body.

The affidavit outlined the disappearance of the mother and daughters.

Shanann Watts returned from a business trip early ‪on Aug. 13‬, dropped off by a friend just before ‪2 a.m.‬ at her home in the 2800 block of Saratoga Trail. Shanann Watts, who was 15 weeks pregnant and not feeling well on the business trip, and the two girls were reported missing about 12 hours later when that same friend became concerned and went to the family’s home.

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The friend discovered that Shanann Watts’ car was parked in the garage and could not get past a latch on the front door, so she called Chris Watts and asked him to come home, fearing Shanann had suffered some kind of medical issue, according to the affidavit.

She also called police.

The first officer at the scene found all the doors and windows were locked. After Chris Watts arrived, he let the officer into the home.

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According to the affidavit, Chris Watts told the officer his wife had come home ‪around 2 a.m.‬, he’d awakened later “and began talking to Shanann about marital separation and informed her he wanted to initiate the separation,” the affidavit said.

“Chris stated it was a civil conversation and they were not arguing but were emotional,” the affidavit said.

A sentencing hearing for Watts is scheduled for November 19 at 10:30 a.m.

Contact 9NEWS reporter Kevin Vaughan with tips about this or any story: kevin.vaughan@9news.com or ‪303-871-1862‬.