A judge on Monday sentenced a Colorado man to life in prison without the possibility of parole after he pleaded guilty earlier this year to killing his pregnant wife and two young daughters in August.

Chris Watts, 33, pleaded guilty to first-degree murder charges for the death of his wife, Shanann Watts, and their children, Bella, 4, and Celeste, 3. At the time of her death, authorities said Shanann Watts was also pregnant with the couple’s third child.

Update 12:55 p.m. EST Nov. 19: Chris Watts was sentenced to multiple life sentences without the possibility of parole.

In an attempt to avoid the death penalty, he had pleaded guilty nearly two weeks earlier to killing Shanann Watts, their unborn son and their two young daughters. Shanann Watts’s parents and brother said in court Monday that they asked prosecutors not pursue the death penalty.

Update 12:40 p.m. EST Nov. 19: An attorney for Chris Watts told the court Monday that he is "devastated by all of this."

“Although he understands that words are hallow at this point, he is sincerely sorry about all of this,” the attorney said.

Chris Watts declined to speak in court.

Update 12:25 p.m. EST Nov. 19: Chris Watts kept his gaze down as Shanann Watts' parents and her brother addressed the court.

“We loved you like a son, we trusted you. Your faithful wife trusted you. Your children adored you and they also trusted you,” said Shanann Watts’ mother, Sandy Rzucek. “But I know God and his mighty angels were there to bring them home to paradise. Not only did you take the family of four -- your family of four -- you took your own life.”

The Rzucek family asked that the court not hand Chris Watts a death penalty sentence for his crime. In statements given in court, family members said they felt they had no right to take his life.

“I trusted you to take care of them not kill them, and they also trusted you, the heartless monster,” Shanann Watt’s father, Frank Rzucek, said as his voice shook in court Monday. “And then you take them out like trash.”

The sentencing hearing for Chris Watts is ongoing.

Original report: According to KMGH, Chris Watts, 33, of Frederick, is slated to appear in Weld County District Court at 10 a.m. MST (noon EST) Monday. Watts, who pleaded guilty Nov. 6 to nine felony charges, including three counts of first-degree murder with deliberation, likely will be sentenced to life in prison without parole, the station reported. Under Watts' plea deal, prosecutors agreed not to pursue the death penalty.

Watts' parents, who recently told KMGH that their son is not a "monster," could speak at the hearing, the station reported. The parents of his wife, Shanann Watts, also could speak, according to KMGH.

Watts is accused of killing his daughters – Bella, 4, and Celeste, 3 – Aug. 12 or 13 in the family’s home. Prosecutors also said Watts killed Shanann Watts, 34, after she returned home from a business trip about 2 a.m. Aug. 13. She was 15 weeks pregnant with a baby boy, whom she planned to name Nico.

A friend reported Shanann Watts missing the afternoon of Aug. 13. Watts was arrested two days later.

According to an arrest affidavit dated Aug. 16, Watts told investigators that Shanann Watts strangled the girls after he asked for a separation around 4 a.m. Aug. 13. He claimed he then strangled her in a fit of rage, the affidavit said.

The affidavit said Watts admitted to burying his wife's body in a shallow grave at a job site belonging to his employer, Andarko Petroleum, about 60 miles from the family's home. The bodies of Bella and Celeste were found in two nearby oil tanks, submerged in crude oil.

At the time of the deaths, Watts had been "actively involved in an affair with a co-worker," the affidavit said.

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In an interview with the Denver Post last week, Nichol Kessinger, 30, said she began dating Watts less than two months before the killings. Kessinger said Watts told her he was at the end of the divorce process, but when his family disappeared, she quickly realized that he had been lying.

"When I read the news, I found out he was still married and his wife was 15 weeks pregnant," she told the Denver Post. "I thought, 'If he was able to lie to me and hide something that big, what else was he lying about?'"

She said called the sheriff Aug. 15 and met with FBI investigators about her concerns. Watts was arrested later that night.

"I don't think there is a logical explanation for what he did," Kessinger told the Post. "It's a senseless act, and it's horrific."

– WSOC-TV contributed to this report.