"American Murder": The Family Next Door, the latest film from Netflix's True Crime division (opens in new tab), presents over an hour of previously unreleased police footage, surveillance cameras, and social media posts from the 2018 Shannan Watts and the murders of her young daughters. Yet, despite all this concrete evidence, the documentary fails to provide a clear answer to the biggest question: why did Chris Watts (opens in new tab) kill his pregnant wife and two daughters?

Chris initially denied any involvement in the disappearance of his family, but eventually confessed to the murders and admitted guilt. Even after his initial confession, however, Chris' story changed. At first he claimed that he killed Shan'an out of revenge for choking 4-year-old Bella and 3-year-old Celeste to death, but eventually admitted that he killed all three and hid their bodies in an oil storage facility where he worked

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And while his full confession stated that the murders were a spontaneous act of anger sparked by an argument with Shan'an over the state of his marriage, Chris later revealed in a letter from prison that he had been planning to kill his family for at least several hours before that. The letter was published in 2019 in Letters From Christopher: The Tragic Confessions of the Watts Family Murders (opens in new tab) by Cheryln Cadle, who struck a correspondence with Chris shortly after he was sentenced to life in prison in November 2018.

In a letter to Cadle, Chris wrote that the night before he killed his wife and daughters, after putting them to bed, "I walked away and said, " I said, 'This is the last time I'm going to put the baby to bed.'" I knew what was going to happen the day before and did nothing to stop it. According to a copy of the letter published in the Daily Mail (opens in new tab), "I was numb to the whole world."

Similarly, in another letter obtained by the paper, Chris describes in harrowing detail how he premeditatedly murdered his wife, writing, "Weeks of thinking about killing her, and now I'm facing it."

The letter also reveals that Chris first tried to smother his daughters in their beds before returning to his own bedroom, where he argued with Shan'an and killed her soon thereafter. But the daughters then "woke up," he writes. He continued, "The act becomes worse when I first go to their room and find out that I am still taking their lives in that place," presumably referring to the facility where he hid the three bodies.

The only reason he offered to justify the senseless killings, and the hypothesis that seems to be put forward in the Netflix documentary, is that the only way he could be with his colleague, Nicole Kessinger (opens in new tab), whom he had secretly begun dating just a few weeks earlier He felt that was the only way. He writes, "I knew that if I ever took my hands off her, she would keep me away from Nicky." Elsewhere in the letter, admitting to Cadle that he tried to cause Shan'an, who was 15 weeks pregnant at the time of her death, to miscarry by giving her oxycodone, Chris wrote, "I thought it would be easier to be with Nicole if Shan'an was not pregnant."

For her part, Kessinger, who says she did not know that Chris was still married during their relationship, became concerned by his eerily calm reaction to the family's disappearance and, after voluntarily approaching the agent to share what she knew, ultimately played a played a key role.