Christopher Watts is in court for his arraignment hearing at the Weld County Courthouse on August 21, 2018 in Greeley, Colorado.
Those who knew the Watts family have described a seemingly happy marriage possibly beset by rising tension, and his infidelity has drawn scrutiny: Authorities have said Chris was cheating with a co-worker when he murdered 34-year-old Shan'ann, Bella, 4, and Celeste, 3.
Shannan was 15 weeks pregnant at the time of her death.
Mr Rourke said the plea deal asks the judge to make the first-degree murder sentences consecutive.
"He deserves a life sentence for each and every act", Weld County District Attorney Michael Rourke said. "I know that that will never be fully realized because, obviously, the tragedy that sits before us today is the loss of four attractive lives (including Shanann's unborn baby)". "And so that's about as firmly as she could have said it to me, and that was very compelling to all of us as we were talking about how to proceed on this case".
Investigators claimed in the documents that Watts admitted to police that he killed his wife.
He struck a plea deal on Tuesday, November 6, in a bid to avoid the death penalty. If it goes as planned, Rourke said he will not fight the release of the autopsy reports for Shanann Watts and her daughters.
Watts pleaded guilty to charges of first-degree murder in the deaths of his wife and daughters and allegations that he killed the girls while in a position of trust. Later, according to his arrest affidavit, Chris claimed he killed Shan'ann in a "rage" at home after watching her strangle Celeste when he said he wanted to separate.
It's alleged he drove their bodies to an oil site, and police said the girls' bodies were found in an oil tank while his wife's body was found in a shallow grave.
Rourke said his office discussed whether to require Watts to provide a full and accurate account of what happened during the slayings, but said everyone involved agreed Watts would never offer a truthful statement.
The family was supportive about not seeking the death penalty, he said.
Hours after the arrest, his family's remains were discovered on property owned by an oil and gas company where he worked.
Rourke said "the spotlight he tried to shine on Shanann, falsely, incorrectly and frankly, a flat-out lie, has been corrected" by his guilty pleas. "The spotlight shines directly where it belongs - on him", Rourke said. He will be sentenced to life in prison without parole.