Convicted family-killer Chris Watts has reportedly shared further details about the murders of his pregnant wife Shannan Watts and their two young daughters, Bella and Celeste.

Watts, who is serving consecutive life sentences after pleading guilty to killing all of his family members, met with investigators from multiple federal and local law enforcement agents last week, according to ABC News. The Colorado Bureau of Investigation told the news outlet in a statement that “Watts provided investigators with additional information about the murders of Shanann, Bella, and Celeste.”

The interview reportedly took place on February 18 at the Dodge Correctional Institution in Waupun, Wisconsin, where Watts was transferred late last year from Colorado as a safety precaution. The CBI told ABC News that the agency expects to release an audio and written file of the interview on March 7, but did not reveal any details about the new information Watts provided about the murders.

Watts’ father Ronnie Watts also said he didn’t know specifically what his son discussed with investigators on February 18, but said, “In my heart I know he didn’t kill those girls.”

Ronnie Watts also told the news station that he didn’t understand why the investigators had gone to Wisconsin to meet with his son.

“It’s over and done with,” he said.