FREDERICK, Colo. – The bodies of Chris Watts’ two young daughters were found inside oil and gas tanks that “were mostly full,” several high-ranking sources tell Denver7’s Jennifer Kovaleski.

The high ranking sources told Kovaleski Thursday evening they believe Watts placed the bodies of 4-year-old Bella and 3-year-old Celeste in the oil and gas tanks owned by Anadarko in order to hide the bodies and conceal the smell.

Frederick police officials said in a 6:30 p.m. update Thursday that the bodies of the two young girls were found in close proximity to the other body whom officers strongly believe is Shanann Watts. Her body was found on property owned by Anadarko Petroleum earlier Thursday. Investigators have not yet confirmed the location of the bodies.

They were recovered as 33-year-old Christopher Watts sat behind bars at the Weld County Jail on suspicion of murdering his family.

Watts was an employee at Anadarko up until Wednesday, the oil and gas company confirmed to Denver7.

The husband and father was taken to jail at 11:30 p.m. Wednesday after he was detained for questioning. Two law enforcement sources told Denver7 Watts had confessed to killing his wife and daughters. He faces investigation on one count of first-degree murder after deliberation; two counts of first-degree murder – position of trust; and three counts of tampering with a deceased human body.

All three were reported missing Monday around 2 p.m. after Shanann did not arrive to a scheduled meeting. In addition to having two daughters, Shanann was also 15 weeks pregnant. The FBI and CBI were brought in to help Frederick police in the investigation.

Weld County prosecutors said they believe Shanann and the girls were killed inside of the family’s home but did not say why they believe that.

MORE: Here's everything we know about the alleged murder of Shanann Watts and her two daughters

There is a candlelight vigil in front of the Watts home scheduled for 8:30 p.m. Friday.