Why Were Mormon Mom Brenda Lafferty And Her 15-Month Old Daughter Murdered? 

When a mother and her 15-month-old daughter were brutally murdered, the crime left a stunned community wondering “why?”

Brenda Lafferty, 24, and her daughter Erica were killed by two assailants who forced their way into their Utah home on July 24, 1984. The pair strangled Brenda “with a vacuum cord, and slit her throat with a knife,” according to court records. They also slashed Erica’s throat, nearly decapitating the child, Deseret News reported in 2019.

And the killers were no stranger to Brenda or her husband, Allen: Ron and Dan Lafferty, who would be convicted of the crime, were Allen's brothers. 

So why would they do such a thing? 

Ron and Dan Lafferty blamed Brenda for helping Ron’s wife leave him. They were also apparently angry that Brenda was against Allen joining their polygamous cult, called School of the Prophets.

But that is just the tip of the iceberg as to why they killed the young Mormon mother.

Ron claimed he heard a revelation from God who told him to “remove” Brenda and the baby in order to keep them from “obstructing God’s work,” the Deseret News reported. He believed that Erica "would grow up to be just as despicable as her mother,” according to court records.

The brothers chose to kill on July 24, the same day that commemorates the Latter-day Saint pioneers’ arrival in the Salt Lake Valley. Ron’s extreme religious views and paranoid delusions had led to his ex-communication from the LDS Church and led to his divorce in 1984, the Salt Lake Tribune reported last year. But Ron put the blame for his divorce on Brenda and Erica, as well as two of Brenda’s friends. He believed that God wanted him to “remove” the two friends as well, according to court records.

Ron Lafferty is escorted out of the Utah County Court House by Utah County Sheriff Deputies after the first day of jury selection in his murder trial April 25, 1985 in Provo, Utah. Photo: Getty Images

Before his conviction, four court-appointed mental health examiners determined that “Lafferty was unable to determine the boundaries between himself and spiritual beings, that he was experiencing ‘blurred ego boundaries,’ that he was suffering from a ‘religious martyr complex,’ that his mind had created a ‘paranoid pseudo-community involving the legal and social systems,’” according to court records. 

Both brothers were convicted of the murders at separate 1985 trials. The case is the inspiration for “Under the Banner of Heaven” a new FX mini-series, which begins streaming on Hulu today. It is also based on Jon Krakauer’s 2003 true crime bestseller “Under the Banner of Heaven,” which details the infamous Utah case, still considered one of the most notorious and gruesome in the state’s history.