GREELEY, Colo. -- Prosecutors face a deadline Monday to formally file charges in the deaths of Shanann Watts and her two daughters.
Weld County prosecutors have spent the past several days trying to determine the charges Christopher Watts will face in connection with the deaths of his wife and two young daughters in their home in Frederick.
The formal charges against Watts are expected to include three counts of first-degree murder and three counts of tampering with a deceased body.
Prosecutors have until 3:30 p.m. Monday to formally file the charges.
An affidavit detailing what led to Watts' arrest is expected to be unsealed later Monday and should reveal a lot about what investigators know about the deaths and the motive.
Watts is being held in protective custody in Weld County. He is due in court Tuesday to be advised of the formal charges.
The Weld County Coroner's Office confirmed the identities on Friday. The cause of their deaths has not been made public.
Shanann Watts' body was found on property owned by Anadarko Petroleum, where her husband, Christopher Watts, worked. Anadarko said it fired Christopher Watts on Wednesday.
The girls were found in an oil well in close proximity to their mother's body, police said.
Defense attorneys asked for DNA samples from the girls' necks, but the motion was denied. The motion seeking the DNA samples from the girls' necks suggested they might have been strangled.
Court documents filed by defense lawyer James Merson said the girls had been submerged in crude oil for four days.
Shanann Watts, who was 15 weeks pregnant, and her daughters were reported missing at 1:40 p.m. on Aug. 13. The Colorado Bureau of Investigation issued a missing-endangered alert for the three on Tuesday.
A close friend has said she dropped off Shanann Watts at home about 2 a.m. Monday when they got home from a work trip. She saw her go inside.
She said the two friends were supposed to meet later in the day, but Watts didn't answer her phone.
Christopher Watts said in an interview Tuesday that he didn't know where his wife and daughters were.