The series is based on the real-life 1984 murders of Brenda Wright Lafferty and her 15-month-old daughter Erica Lafferty.
The town of Rockwell is fictional, and the real Lafferty case occurred in the town of American Fork, Utah.
Josie's dementia sometimes leads her to refer to aspects of LDS doctrine that were once accepted but that are now officially frowned upon. One example of this is when she starts to rant about the salvation of Jewish people. She says: "The Jews, they need baptisms. . . . You know, if the Jews don't accept Christ, they . . . they're gonna find themselves in the Celestial Kingdom with Hitler." Jeb and Rebecca ask her to stop saying that kind of thing because it scares their daughters. In 1994, it was revealed that the Church of Jesus Christ of Latter-day Saints was regularly performing posthumous proxy baptisms for Jewish people, including Holocaust victims. This scandal enraged Jewish people worldwide, since it obliviously echoed the forced conversions and persecutions that Jews were obliged to undergo at many points across history. Though the LDS Church promised to stop proxy-baptizing those who died in the Holocaust, and other Jewish people, it was later revealed that this practice continued with such well-known Jewish figures as Daniel Pearl and Anne Frank.
Series creator and adapter Dustin Lance Black was himself raised in the LDS Church, a background he found helpful in his work on this miniseries. In a July 2022 interview with Kim Masters on KCRW's show "The Business," he said, "I saw my mother being abused [and] the church preferring she lean on church authority, as opposed to police authority, and that really didn't resolve things because, it's the woman's place in Mormon home to create a home suitable to her priesthood holder [or] the father in the home. But the thing that's most disturbing about having witnessed that is how unremarkable it was. It was not just her. My mother was the president of the Relief Society in our area, which is the women's group in the church, and I was keenly aware that our story was not special." However, he also said that he was "very attached" to the church as a teen, despite the discomfort he felt with its intolerant policy on LGBTQ rights and his growing realization that he was gay: "I was devout. I didn't know any different. It's how the design of the church is. I was six days a week in church, which I enjoyed, whether that's Sunday school, or Boy Scouts. It was all Mormon, and it's all I knew. And it felt very safe. So leaving the church was not something I wanted to do, [but] I followed my mother out as a teenager." Black was also a staff writer on the TV series "Big Love," about a modern polygamous Mormon family.
This is the second religious/cult themed projects Rory Culkin has been in, the first being Waco (2018). He subsequently played a Charles Manson-like murderous cult leader in the Black Mirror episode "Beyond the Sea."