The two young girls were strangled and their bodies were found inside an oil tank, the Denver Post reported, citing a motion filed in court by an attorney for Watts.
Christopher Watts's attorneys sought to preserve DNA evidence they said would still be present on the bodies, saying that once autopsies are finished, the evidence will be "lost forever", according to the motion.
They also remembered Watts' children: four-year-old Bella and three-year-old Celeste. More testing is planned to help determine the cause of their deaths.
He also recommended taking DNA samples from the girls' hands and the nails and hands of Shanann Watts.
Eikelenboom is a forensic scientist who has testified as a DNA expert in trials across Colorado.
After his family was missing, Mr Watts told reporters he had desperately tried to contact his wife. Krista Henery, a spokeswoman for the Weld County District Attorney's Office, said the formal filing of charges is not expected until at least Monday.
He was taken into custody late Wednesday, and on Thursday police discovered the bodies of Shanann, Celeste and Bella at an oil drilling field where Watts worked as an operator for Anadarko.
The adult woman's body was found on the property of Anadarko Petroleum Corporation.
Watts was sacked on Wednesday, the same day he was arrested, the company said.
Chris Watts was in court at 2:30 p.m. Thursday afternoon.
Watts' attorney, James Merson of the Colorado state public defender's office, also left court without commenting.
Authorities have declined to confirm media reports that Watts had confessed to killing his family.
"I love Chris! He's the best dad us girls could ask for", Shanann Watts wrote in a Facebook post sharing the text exchange with her husband.
The couple had a combined income of $90,000 in 2014.
Still, they were about $70,000 in debt, most of it from student loans and credit card purchases, according to the filings.
They said in the filing that their almost $3,000 mortgage and $600 in monthly auto payments formed the bulk of their $4,900 in monthly expenses.
Shannan Watts' two young daughters.
Wednesday night, Chris was arrested on suspicion of three counts of first-degree murder, and three counts of tampering with deceased bodies. He's expected to be formally charged by Monday.
No motive has been released, leaving family and friends searching for answers. Shanann was an awesome woman, mother, friend, and overall person. Their daughters played together during salon visits.
"I call it a highway to heaven", said neighbour Mary Ann Bogner, 64, fighting back tears as she arranged candles in the form of a cross.
Kelley Trippy, a neighbor, said the murders have shocked the community.
"We were talking about general things", he said, "about how her two girls were doing and how life was out in Colorado. She seemed pretty happy".
Ashley Bell, a friend of Shanann's told local TV station KDVR that a gender-reveal party for Shanann Watts' unborn child was scheduled for Saturday.
Proposals to change the law have been stymied by debate about when a fetus can legally be considered a human being.
Republican lawmakers last tried to change the law after a 2015 case in Boulder County. The baby was going to be named Nico, the post says. Prosecutors said they could not charge Lane with murder because a coroner found no evidence the infant lived outside the womb.