Chris Watts still loves the mistress and wanted to be her with so much he slaughtered his family. But he laments that he would not be in prison if it was not for her.
'If I had not met Nikki, I would never have killed my family,' he told author Cherlyn Cadle in letters and interviews for her explosive upcoming book, Letters from Christopher.
'He was mesmerized by her. She showed him respect that he didn't feel like he'd ever been shown before,' Cadle told DailyMailTV in an exclusive interview.
Watts also claims to still love Nichol Kessinger, the mistress he met at work and had been seeing for two months when he decided to murder his pregnant wife Shanann, and daughters Bella, 4, and Celeste 3, so that he could be with her.
The 34-year-old was so enamored with Nichol, he even tried to cause Shanann to miscarry their son Nico, giving her the powerful painkiller Oxycodone, after Nichol told Watts she wanted to 'give him his first son.'
'Christopher says he loved her like he has never loved anyone else before,' Cadle said. 'At the same time, he loves Shanann although he knows that she was not his soulmate and not the person he was supposed to be with.'
Watts has wondered about where Nichol is, and told Cadle he has received some letters and postcards, signed with different names, and wonders if they might be from the woman he does call 'his soulmate.'
Watts, 34, confessed his deepest feelings to Cadle, a 65-year-old grandmother from Illinois, who wrote him a letter earlier this year asking if he would take part in a book to put to rest any lingering questions about the case.
To her great surprise, he agreed. The book, Letters From Christopher, is on pre-order and will be published October 7.
Chris Watts claims if he hadn't met his mistress Nichol Kessinger, he wouldn't have killed his wife Shanann and their two little girls, DailyMailTV can reveal. Author Cherlyn Cadle claims Watts 'was mesmerized by her'
Watts also claims to still love Nichol, the mistress he met at work and had been seeing for two months when he decided to murder his family at their home in Fredrick, Colorado last August
'Christopher says he loved her like he has never loved anyone else before,' Cadle added. 'At the same time, he loves Shanann although he knows that she was not his soulmate and not the person he was supposed to be with.' Pictured: Watts with Shanann and their daughters
After the murders, Watts told Cadle: 'All I could feel was now I was free to be with Nikki. Feelings of my love for her was overcoming me. I felt no remorse.
'The darkness inside of me had won, it was still in me, though, I thought maybe permanently. I felt evil, swallowed up by this thing inside of me. I felt like I could kill anything and be justified for doing it.
Cadle later wrote: 'After Christopher killed his family and drove away, Nikki texted him to look up the song by Metallica band called ''Battery.'' I challenge you to look up the full lyrics of this song. I find it interesting that we should believe it's only a coincidence.'
As part of her research, Cadle spent 15 hours meeting face-to-face with Watts in prison, had phone calls three times a week and exchanged dozens of letters.
Cadle is unsure why he responded to her amid dozens of interview requests and the hundreds of letters he receives.
Watts has confessed his deepest feelings to Cadle, a 65-year-old grandmother. He agreed to let her use his letters for her upcoming book Letters From Christopher
'I think he responded because I felt like, even though it was such a heinous crime, that he could still be used in prison to help other people. It was clear that he felt the same way. So I think when I wrote that, maybe no one else had said that to him.'
Watts agreed to allow Cadle to use his letters in exchange for publishing his 'testimony of coming to God and the forgiveness he received'.
'The agreement was he would take no money for himself or his family,' she said.
Last November, Watts was sentenced to five life sentences without the possibility of parole after pleading guilty to avoid the death penalty.
In August 2018, he had strangled his pregnant wife Shanann, 34, in their bed at their home in Frederick, Colorado, also causing the death of his unborn son, Nico.
Then he drove his daughters, Bella, 4, and Celeste, 3, to a remote oil field where he worked, and smothered them in their blankets before squeezing their bodies through eight-inch hatches and dropping them into oil tanks.
'I couldn't believe how easily it was to just let her drop through the hole and let her go. I heard the splash as she hit the oil,' he said of Celeste.
He then relived for Cadle, in appalling detail, how he killed his eldest daughter Bella after she had watched him murder and dispose of her baby sister. He spoke of his surprise that: 'Little quiet Bella had a will to live.
'Out of all three, Bella is the only one that put up a fight. I will hear her soft little voice for the rest of my life, saying, 'Daddy, NO!!! She knew what I was doing to her. She may not have understood death, but she knew I was killing her.'
He has repeatedly told investigators that his daughters were not alive when they went into the tanks and that he had intentionally separated their bodies.
He rolled his pregnant wife's body into a shallow grave.
As part of her research, Cadle spent 15 hours meeting face-to-face with Watts in prison, had phone calls three times a week and exchanged dozens of letters. Cadle is unsure why he responded to her amid dozens of interview requests and the hundreds of letters he receives
Watts has wondered about where Nichol is, and told Cadle he has received some letters and postcards, signed with different names, and wonders if they might be from the woman he calls 'his soulmate'
The 34-year-old was so enamored with Kessinger he even tried to cause Shanann (above) to miscarry their son Nico, giving her the powerful painkiller Oxycodone, after Kessinger told him she wanted to 'give him his first son'
'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,' he later said.
The autopsy confirmed that Shanann's amniotic sac containing the fetus was protruding from her vaginal area.
Watts later tried to falsely blame Shanann for her daughters' murders, claiming that he had seen her killing them on the baby monitor in their bedroom and he attacked her in a blind rage.
The sentencing judge called it 'perhaps the most inhumane and vicious crime I have handled out of the thousands of cases that I have seen'.
Like everyone else, Cadle was horrified by the brutality of the murders. The 65-year-old, who has previously published short stories in her local paper, had followed big cases like OJ Simpson and JonBenet Ramsey but never felt compelled to take action before.
'The first morning that I saw Christopher on television, it just struck me there was such a lost look about him,' she said. 'I wanted to find out why. He had such a beautiful life, a beautiful family. What would cause someone to do something like this?'
She wrote her first letter in February. In a matter-of-fact tone, she laid out her intentions to write a book, saying she had never been in doubt of his guilt.
'Let me just say, the crime was horrific, so I'm not writing you to tell you how wonderful you are or that I want to be pen pals,' Cadle wrote.
Cadle told DailyMailTV: 'I never believed that he only killed Shanann and that she killed her daughters. A mother who was vibrant, full of life, with happy, beautiful children that she took very good care of, there is no way she could have ever done that.'
Cadle's first letter didn't reach Watts but after she wrote twice more, he replied. He also had his mother, Cindy Watts, call Cadle.
Cadle wrote her first letter to Watts in February. In a matter-of-fact tone, she laid out her intentions to write a book, saying she had never been in doubt of his guilt. Eventually they built up a correspondence, with Watts telling her about his life and the murders. Pictured: Watts writing to Cadle in April
Following the shocking letter about his daughters' ordeal, Cadle said she was left with many questions, which Watts answered in later conversations. Pictured: One of the letter envelopes sent from Watts to Cadle
'Christopher asked her to call me and let me know that he was interested in doing the book and would like to talk to me.
'He told me secrets that he had held. When the FBI came to see him in February, he didn't know they were coming and felt surprised and disgruntled over that.
'His story that he gave them at that time is true for the most part. There were just more specifics of how the murders took place and some of the things that he did.'
After a few more letters and a prison background check, Cadle made the drive to Dodge Correctional Institute in Waupun, Wisconsin, to meet him. She went into the prison alone.
'It was intimidating. It's a thorough screening, you can't even have metal hooks in your clothing. My hand was stamped and I went through seven locked security doors before I got to where Christopher was being held. Each time, you are in a short hallway and the last door clicks behind you.'
Their first face-to-face meeting was conducted via video screen because Watts was still in solitary confinement.
'The other prisoners were yelling and mad because they had to be locked down in their cells while guards brought him through the hallways.
'He was handcuffed to the table and his feet were shackled. It seemed sad with so much security in the prison, they still considered him very much a threat.'
The next two visits took place in the general visiting hall, alongside other families. The room is lined with vending machines and Cadle had brought in $20 dollars of quarters, the maximum allowed.
'I bought him a cheeseburger, a bag of potato chips, two Mountain Dews and a candy bar. It's a taste outside of the prison food.'
Last November, Watts was sentenced to five life sentences without the possibility of parole after pleading guilty to avoid the death penalty. Pictured: Watts in a Colorado prison a month before he was sentenced
After the murders, Watts told Cadle: 'All I could feel was now I was free to be with Nikki. Feelings of my love for her was overcoming me. I felt no remorse'
Watts' shackles were removed in the main visitor hall and Cadle was able to give him a hug when he entered. He was then ordered to stay in his chair and no other physical contact is allowed.
When she finally met Watts in person, she was taken aback.
'He was more boyish and friendly than I had expected. He had shaved his facial hair, so he looked different. The voice was like I had heard on TV. It's a kind voice, actually.'
Cadle was perturbed by the fact that Watts was unable to make eye contact as they spoke.
'I finally said, why can't you look at me when you talk to me? He replied, 'I have always been that way. It's not because of you.'
They talked about what life was like for him in a high-security prison.
'In solitary, he was locked up 23 hours a day. It's a small cell and not air conditioned,' Cadle said. 'He came from an almost palatial and now he's confined to this little cell. He has absolutely nothing.'
As security was slightly relaxed, Watts gained more privileges. 'He can go to a day room for a few hours, maybe watch TV. He's picked up playing chess.'
At Dodge Correctional Institute, Watts has his own cell in a wing of around 17 inmates with special