WELD COUNTY, Colo. (CBS4)– Charges have officially been filed against Chris Watts, the man accused of killing his pregnant wife and two young daughters. Watts faces five counts of first degree murder, unlawful termination of a pregnancy and three counts tampering with deceased human body.

Two of the five murder charges specify the murder of a victim under the age of 12 by a person in a position of trust. All charges are felonies.

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The body of Shanann was found buried in a shallow grave near an oil tank where the bodies of her daughters were found on Anadarko Petroleum property.

Court documents suggest Bella and Celeste were killed between Aug. 12 and Aug. 13. Shanann returned home on Aug. 13.

Chris Watts (credit: CBS)

Police arrested Chris Watts, 33, late Wednesday on suspicion of killing his wife and children.

The bodies of the pregnant mother and her daughters were discovered days after they were reported missing from their home in Frederick.

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Shanann Watts and her daughters’ bodies were found Thursday on property owned by Andarko Petroleum, one of Colorado’s largest oil and gas drillers, where Watts worked as an operator.

Autopsies were completed Friday on Shanann Watts, 34, and her daughters, 4-year-old Bella and 3-year-old Celeste.

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According to court documents, the girls had been submerged in crude oil for four days.

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During a news conference on Monday, the Weld County District Attorney, Michael Rourke, said an affidavit would be released in the afternoon. He also said Watts will be advised of his charges on Tuesday.

When asked if his team would be seeking the death penalty, Rourke said, “It’s way too early to make that determination.”

The couple had financial problems and filed for bankruptcy in 2015, but so far investigators have not revealed a motive for the killings.

Chris Watts (credit: Weld County)

Shanann’s father and brother were also at Monday’s news conference.

“We would like to thank everyone and the Frederick Police Department and all the agencies involved for working so hard to find my daughter, granddaughters and Niko. Thank you everyone for coming out to the candelight vigil and saying all your prayers. They are greatly appreciated. Keep the prayers coming,” Frank Rzucek said.

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Outside the family’s home in Frederick, north of Denver, a memorial of stuffed animals, balloons, flowers and messages continues to grow.