Chris Watts described murdering his children 'more than once' in harrowing letters from behind bars

Warning: this article contains details some people may find upsetting

Chris Watts described murdering his children 'more than once' in sick letters from his prison cell in Wisconsin.

The murderer, 37, is currently serving five life sentences for killing his pregnant wife Shanann and their two daughters, Bella, four, and Celeste, three.

The killer opened up about his crimes in a series of letters to author Cheryln Cadle, which she later published her book, The Murders of Chris Watts.

Watts wrote that he had been 'thinking about killing' his wife for weeks and explained that it took two attempts before he was able to kill his daughters.

The twisted killer tried to smother his daughters before murdering his wife, whose 'eyes filled with blood' and her face got 'all black with streaks of mascara'.

Watts wrote: "August 13, morning of, I went to the girls' room first, before Shanann and I had our argument.

"I went to Bella's room, then Cece's room and used a pillow from their bed [to kill them].

"That's why the cause of death was smothering. After I left Cece's room, then I climbed back in bed with Shanann and our argument ensued."

Cheryln Cadle

After failing to take his daughters' lives, they woke back up.

The girls then followed him around as he was in the process of disposing of their pregnant mother's body.

He said: "After Shannan had passed, Bella and Cece woke back up. I'm not sure how they woke back up, but they did.

"Bella's eyes were bruised and both girls looked like they had been through trauma."

He then successfully killed the toddlers, explaining that 'Bella is the only one that put up a fight' as 'she knew I was killing her'.

The killer then disposed of all three bodies as he planned to start a new life with his secret lover, Nicole Kessinger, which was detailed in a Netflix documentary about the crimes.

He dumped his daughters in oil barrels and buried his wife, admitting that he was still angry at her when he realised she'd posthumously given birth.

He added: "When I dug the hole, it seemed a lot deeper than it was. As I pulled on the sheet she rolled out and into the hole.

"I think she had given birth. She landed face down, I remember being so angry with her that I was not going to change how she landed."

Netflix / American Murder: The Family Next Door

When Watts initially admitted to his heinous crimes, he said that the murders were spontaneous, before later admitting that he had planned them.

Watts revealed: "August 12 when I finished putting the girls to bed, I walked away and said ''That's the last time I'm going to be tucking my babies in'.

"I knew what was going to happen the day before and I did nothing to stop it."

Watts' life sentences were issued without the possibility of parole, and he will spend the rest of his life in prison.