An unidentified young boy places a bouquet of flowers on a pile of tributes outside the home where a pregnant woman and her two daughters lived Thursday, Aug. 16, 2018, in Frederick, Colo. The woman's husband has been arrested in the disappearance of the woman and children. Authorities say that they have found the woman's body and believe to know the whereabouts of the two girls. (AP Photo/David Zalubowski)

DENVER | A Frederick man told police that he killed his pregnant wife for strangling their daughters after he sought a separation.

According to an arrest affidavit unsealed Monday, Christopher Watts told his wife, Shanann, that he wanted to separate when she returned from a business trip.

Watts told police that shortly after, he saw his wife strangling their youngest daughter and their older daughter sprawled on her bed via a baby monitor.

Watts said he then “went into a rage” and strangled his wife.

He told police that he loaded all three bodies into his work truck and he buried his wife at an oil work site and dumped his daughters inside oil tanks.

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 charges against Watts come a week after a friend reported Shanann Watts, 34, and the girls missing from their home in Frederick.

Authorities found the body of Shanann Watts’ Thursday, buried in a shallow grave near an oil tank on property owned by Anadarko Petroleum, which employed Christopher Watts. The bodies of 4-year-old Bella and 3-year-old Celeste were later found inside oil tanks near their mother’s grave.

Christopher Watts is being held without bail and will next appear in court Tuesday.

Court documents filed by defense lawyer James Merson said Bella and Celeste had been submerged in crude oil for four days.

Autopsies have been completed but not released.

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