More detail in killings expected next week

Colorado authorities prepared Friday to file formal charges against an oil and gas worker accused of killing his pregnant wife and two young daughters inside their suburban home, then dumping their bodies on his employer’s property.

Police said the mother, Shanann Watts, was found dead on property owned by Anadarko Petroleum, one of the state’s largest oil and gas drillers, where 33-year-old Christopher Watts worked as an operator. Investigators found what they believe are the bodies of 4-year-old Bella and

3-year-old Celeste nearby on Thursday.

The operator position generally charges employees with routine visits to oil fields, checking on the status of wells, maintaining the equipment and fixing any issues. Watts was fired on Wednesday, the same day he was arrested, the company said.

The family’s two-story home is just outside Frederick, a small town on the grassy plains north of Denver, where fast-growing subdivisions intermingle with drilling rigs and oil wells.

According to a June 2015 bankruptcy filing, Christopher Watts had gotten a job six months earlier as an operator for Anadarko, and paystubs indicate his annual salary was about

$61,500. Shanann Watts was working in a call center at a children’s hospital at the time, earning about

$18 an hour — more for evenings, weekends or extra shifts she sometimes worked.