The Colorado monster convicted of murdering his family told investigators in a newly released interview that his wife didn’t fight back — and may have turned to prayer — as he was choking her to death.

Chris Watts, 33, revealed in a Feb. 18 prison interview that he started strangling his wife, Shanann, in their bed on Aug. 13 after he said he didn’t love her — and she threatened to leave with the children.

“Every time I think about it, I’m just like, did I know I was going to [strangle her] before I got on top of her?” he said, according to a Colorado Board of Investigation report detailing the interview.

Shanann looked back at him, but didn’t struggle or scream, Watts told investigators.

She may have started praying instead, he said.

In reading the Bible, Watts came across the verse, “Forgive these people for they do not know what they do.”

“Maybe Shanann was saying that in her head at the time,” he said.

The prison interview marked the first time Chris Watts has confessed publicly to the murder of his daughters, Celeste, 3, and Bella, 4. He had previously confessed to killing Shanann but only because, he claimed, he saw her abusing Celeste.

The interview also reveals that Watts loaded Shanann’s body into the back seat of his truck with their two daughters.

Then he drove out to a Weld County oil site, where he pulled his wife’s body from the truck and laid her on the ground, near where she was ultimately buried.

“What are you doing to Mommy?” he said his small daughters asked him.

Then he smothered the girls one at a time and dumped them in an oil tank — with little Celeste as his first victim, according to the report.

After watching what happened to her little sister, Bella asked her dad, “Is the same thing gonna happen to me as Cece?”

Then he smothered his older daughter, who didn’t give up without a fight, according to the report.

Her last words were, “Daddy, no!,” Watts claimed.

Every time he closes his eyes, he told investigators, he hears Bella saying those words.

Watts has a book in his prison cell that he used to read to Celeste, he shared in the interview.

“He reads the book to his daughters, along with some Scripture, every night,” the report says. “He wished it never happened and he never had a blinder over his eyes and could have seen what was going on.”

Watts was sentenced in November, and is serving multiple life sentences in a Wisconsin prison.