FREDERICK, Colo. (KABC) -- Colorado father Christopher Watts, who has been accused of killing his pregnant wife and two young daughters, has been charged in the case.
Watts faces nine felony charges, including three first-degree murder charges, two counts of murdering a child, one count of unlawful termination of a pregnancy and three counts of tampering with a deceased human body.
The bodies of Watts' wife, 34-year-old Shanann Watts, and two daughters, 3-year-old Celeste and 4-year-old Bella, were found last week on the property of Anadarko Petroleum, one of Colorado's largest oil and gas drillers.
Records show Christopher was employed by the company in 2015.
Authorities in Colorado were expected to release an affidavit sometime Monday explaining why investigators believe Watts killed his family.
Before his arrest last week, Christopher Watts lamented in interviews with local television stations about missing his wife and daughters. No motive has been released.
Officials said the bodies of the young girls were found inside oil and gas tanks that "were mostly full." Investigators believe Christopher placed the girls in there to conceal the smell from passersby.
Shanann was reported missing on Aug. 13 by her friend Nickole Atkinson after she missed a doctor's appointment.
Atkinson said she felt something was off and called police.
Atkison spoke exclusively with Good Morning America, saying things almost seemed too perfect.
A judge on Friday denied a request by defense lawyer James Merson to require the coroner to collect DNA from the necks of the children. The attorney's request suggested that the girls may have been strangled.
Christopher Watts is being held without bail and will next appear in court Tuesday.
The Associated Press contributed to this report.