Under the Banner of Heaven: A Story of Violent Faith is a nonfiction book by author Jon Krakauer, first published in July 2003. He investigated and juxtaposed two histories: the origin and evolution of the Church of Jesus Christ of Latter-day Saints (LDS Church) and a modern double murder committed in the name of God by brothers Ron and Dan Lafferty, who subscribed to a fundamentalist version of Mormonism. The Laffertys were formerly members of a very small splinter group called the School of Prophets, led by Robert C. Crossfield (also known by his prophet name Onias). The group accepts many beliefs of the original LDS church at the time when it ceased the practice of polygamy in the 1890s, but it does not identify with those who call themselves fundamentalist Mormons. The book examines the ideologies of both the LDS Church and the fundamentalist Mormon polygamous groups, such as the Fundamentalist Church of Jesus Christ of Latter-Day Saints (FLDS Church). The book was adapted as a limited series of the same name that began airing in April 2022 on FX on Hulu. Synopsis Murders The book opens with news accounts of the 1984 murder of Brenda Lafferty and her infant daughter Erica. Brenda was married to Allen Lafferty, the youngest of the Lafferty brothers. His older brothers Dan and Ron disapproved of their sister-in-law Brenda because they believed she was the reason Dan’s wife left him (after refusing to allow him to marry a plural/second wife—his stepdaughters). Both men's extremism reached new heights when they became members of the School of the Prophets, founded and led by Robert C. Crossfield. After joining this group, Ron claimed that God had sent him revelations about Brenda. Communication with God is a core belief of fundamentalist Mormonism, as well as the mainstream LDS Church. Ron showed the members of the School of Prophets a written "removal revelation" that allegedly called for the killing of Brenda and her baby. After other members of the School failed to honor Ron's removal revelation, the brothers quit the School. Dan claimed that he slit both of the victims' throats. But, at the 2001 trial, Chip Carnes, who was riding in the getaway car, testified that Ron said that he had killed Brenda, and that Ron had thanked his brother for "doing the baby". After the murders, the police found the written "revelation" concerning Brenda and Erica.