Christopher Watts glances back at a Weld County Sheriff's Deputy as he is escorted out of the courtroom at the Weld County Courthouse Thursday, Aug. 16, 2018, in Greeley, Colo.

Joshua Polson/The Greeley Tribune via AP, Pool

Published 7:09 a.m. | Updated 11:07 a.m.

Christopher Watts was sentenced to life in prison without parole on Monday after pleading guilty to murdering his pregnant wife and their two young daughters and dumping their bodies on an oil work site.

The Frederick man pleaded guilty on Nov. 6 to three charges of murder in the deaths of his wife, Shanann Watts, and their young daughters. He also pleaded guilty to two counts of murdering a child, one count of unlawful termination of a pregnancy and three counts of tampering with a deceased human body.

Weld County District Court Judge Marcelo Kopcow said this case was "perhaps the most inhumane and vicious crime" he has handled in his 17 years on the bench. "Anything less than the maximum sentence would depreciate the seriousness of this offense."

Watts' representation shared his short statement that said their client was, "devastated by all of this and, although he understands that words are hollow at this point, he is sincerely sorry for all of this."

Prosecutors asked for consecutive life sentences for the murder charges. Watts received three consecutive life sentences in the Colorado Department of Corrections plus another 84 years for unlawful termination of a pregnancy and three counts of felony tampering with deceased bodies.

They agreed not to seek the death penalty in exchange for Watts' guilty plea, after they sought approval from Shanann Watts' family. First-degree murder charges in Colorado require a minimum sentence of life without a chance at parole for adults.

Representation for Watts' parents spoke at the sentencing Monday. The parents, Cindy and Ronnie Watts, did not ask for leniency in sentencing but asked for an opportunity for Christopher Watts to make a more detailed confession.

Judge Marcelo Kopcow also ruled Thursday that Christopher Watts' parents are considered victims of the crime because they are the girls' grandparents. Victims are allowed to give a statement or provide written comments during sentencing hearings in Colorado.

A friend asked police to check on Shanann Watts on Aug. 13 when she could not reach her and grew concerned that the 34-year-old who was pregnant with a third child missed a doctor's appointment. Local police initially handled the search and soon sought support from Colorado investigators and the Federal Bureau of Investigation.

Meanwhile, Christopher Watts spoke to local television reporters from the front porch of the family's home in Frederick; a small town on the plains north of Denver where drilling rigs and oil wells surround booming subdivisions. Watts pleaded for his family to return home, telling reporters their house felt empty without four-year-old Bella and three-year-old Celeste watching cartoons or running to greet him at the door.

Within days, the 33-year-old was arrested and charged with killing his family.

According to court records, Watts admitted to police that he killed his wife. Watts told investigators that he strangled her in "a rage" when he discovered she had strangled their two daughters after he sought a separation.

Prosecutors have since called Watts' account "a flat-out lie."

Authorities have not released autopsy reports or any information about how the mother and daughters died. Prosecutors have said the reports would be released after Christopher Watts' sentencing.

The girls' bodies were found submerged in an oil tank, on property owned by the company Christopher Watts worked for until his arrest. Shanann Watts' body was found buried nearby in a shallow grave.

Police also learned that Christopher Watts was having an affair with a co-worker. Watts had denied that before being arrested.

The killings captured the attention of media across the country and became the focus of true crime blogs and online video channels, aided by dozens of family photos and videos that Shanann Watts shared on social media showing the smiling couple spending time with their children and each other.

Courts records, though, showed the couple's lifestyle caused financial strain at times. They filed for bankruptcy in June 2015, six months after Christopher Watts was hired as an operator for the large oil and gas driller Anadarko Petroleum at an annual salary of about $61,500. At the time, Shanann Watts was working in a children's hospital call center for $18 per hour.

They reported total earnings of $90,000 in 2014 but $70,000 in unsecured claims along with a mortgage of nearly $3,000. The claims included thousands of dollars in credit card debt, some student loans and medical bills.

CPR's Natalia Navarro contributed to this report.