Being a convict murderer is not an easy task.

SoThe Banner of Heaven stars Sam Worthington and Wyatt Russell knew they had their work cut out for them when they agreed to play Ron and Dan Lafferty, two brothers who killed their sister-in-law, Brenda Lafferty, 24, her 15-month-old daughter, Erica, in 1984. (The brothers, who came from a devout prominent Mormon family in Utah, claimed that God ordered them to commit the crimes.)

Worthington told CelebHomes News that he couldn’t begin to understand what would motivate someone to do such a thing. And then he realized through working with writer Dustin Lance Black that “you can’t play delusional, but you can play someone that is passionately pursuing something.”

In the series, the Laffertys appear to be a normal, loving family, begging the question: “How could this event happen in such a pious and devoted community? “In such a loving and caring family?” Worthington shared his thoughts. “So the more I strengthened and leaned into a man that would do anything for the love of his kids and for the love of his wife, it gave me a touchstone of how to play certain scenes.”