Shannan Watts Says Chris Is 'Best Thing that Has Ever Happened to Me' in Trailer for Netflix Series

A new true crime documentary on Netflix investigates the 2018 murders of pregnant mom Shanann Watts and her two daughters

Chris and Shanann Watts.

On August 13, 2018, Chris Watts killed his pregnant wife and two young daughters.

The details of the crime were especially brutal: He strangled his 34-year-old wife, Shanann, in their Colorado home, and then smothered his daughters — Bella, 4, and Celeste, 3 — at his job site on an oil field. Watts pleaded guilty and was sentenced to life in prison without the possibility of parole.

On September 30, Netflix will release a new documentary entitled American Murder: The Family Next Door. The documentary will investigate the private lives of Chris and Shanann Watts through archival footage and police videos.

Central to the documentary are some of Shanann's social media videos. While her husband was having an affair behind her back, Shanann was telling her followers about a picture perfect life in a suburb of Denver.

"I just want you to know a little bit of my story," Shanann told her followers in a Facebook video just weeks before her death. "I went through one of the darkest times of my life and then I met Chris and he's the best thing that has ever happened to me."

Now, Shanann is dead and Chris is housed at Dodge Correctional Institution, a maximum-security prison, in Waupun, Wisconsin, after pleading guilty to the murders. (He was moved out of Colorado for security reasons.)

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Shanann (left) and Chris Watts. Facebook

Last November, a source told PEOPLE that Watts had found religion in prison, and that he reflects on his sins daily. “A day doesn’t go by — a minute doesn’t go by — where he doesn’t think about his family,” the source said. "He's in a hell of his own making."

In 2019, Watts agreed to pay Shanann's family $6 million to settle a wrongful death civil suit.

“The Rzucek family has not been the same since August 13, 2018,” court documents from the suit obtained by the Denver Post read. “They have suffered with anger, loneliness, sadness, and depression. For a substantial period of time following the discovery of their daughter and grandchildren’s murders, they were unable to work, leave the house, or even eat.”

American Murder: The Family Next Door begins streaming on Netflix Sept. 30.