Chris watts told daughter 'mommy's sick' after she saw him disposing of wife's dead body

A lawyer for the family of slain Colorado mom Shanann Watts is speaking out on _Dr. Phil_ — and sharing disturbing details of the day Chris Watts strangled his wife and smothered his two

young daughters. A pre-recorded interview with attorney Steven Lambert will appear on Tuesday’s episode of _Dr. Phil_. In a clip of the interview obtained by PEOPLE, he alleges that

4-year-old Bella walked in on her dad disposing of her mom’s body by wrapping it in a sheet. “Bella walked in and asked, ‘What are you doing with Mommy?'” said Lambert. According to

Lambert, Watts told his daughter, “Mommy is sick, and we need to take her to the hospital to make her better.” At some point after that conversation, Watts smothered Bella and her 3-year-old

sister, Celeste. He then loaded their bodies into his truck and hid them on an oil work site where they were found three days later. _• WANT TO KEEP UP WITH THE LATEST CRIME COVERAGE?

__CLICK HERE__ TO GET BREAKING CRIME NEWS, ONGOING TRIAL COVERAGE AND DETAILS OF INTRIGUING UNSOLVED CASES IN THE TRUE CRIME NEWSLETTER._ In November, Watts pleaded guilty to all three

killings. He is currently serving five life sentences without the possibility of parole. Watts was having an affair with a co-worker at the time of the killings. Authorities have cited his

desire for a “fresh start” with his mistress as his motive for the killings. According to Lambert, the murder happened after an argument about the affair. “In that fight, [Chris] essentially

confessed to having an affair, that he wanted a divorce, that it was pretty much over between them,” Lambert told McGraw. “[Shanann] said something to the effect of, ‘Well, you’re not going

to see the kids again.’ As a consequence of that conversation, he strangled her to death.” A February 18 statement to PEOPLE from the Colorado Bureau of Investigation says that authorities

“interviewed Christopher Watts for the purpose of developing further insight into the case. Watts provided investigators with additional information about the murders of Shanann, Bella, and

Celeste during the interview.” A spokeswoman from the Colorado Bureau of Investigation tells PEOPLE the office plans to release more information on the case Thursday, adding that the office

was taken by surprise by the _Dr. Phil_ interview. A spokesperson for the Weld County District Attorney’s Office tells PEOPLE the office is not releasing any more information on the case.