John R. Llewellyn is a retired Salt Lake County Sheriff's Lieutenant who specialized in the investigation of sex crimes which included polygamy complaints. He compiled an intelligence file on mass murderer, Ervil LeBaron, who in 1977 ordered the death of Doctor Rulon C. Allred, leader of Utah's second largest polygamist group. LeBaron, a self-imposed "One Mighty and Strong," attempted to extort tithing from Utah's polygamist groups. John’s first novel, Murder of a Prophet, is a paradigm of the Allred murder, and factual expose´ of the dark side of Utah polygamy.

While a deputy, in order to best combat and understand the polygamist, Llewellyn studied and researched Mormon doctrine which lead to his conversion to the LDS Church, and ultimately, Mormon fundamentalism. Impressed with the integrity, virtue and undaunted conviction of many of the polygamists, after his retirement, Llewellyn became a member of Apostolic United Brethren, Utah’s second largest polygamist group. However, when the leadership of AUB re-postured, claiming absolute authority over all of Mormondom, including the LDS Church, Llewellyn took a second look at the fundamentalist belief structure and summarily disassociated himself.

He no longer believes in any organized religion and takes the position that he wants no middle man between him and God, not a pope, prophet or priest, and if there is an afterlife, he will take care of his own salvation.

In 1995, Llewellyn became an investigator for Virginia Hill in a civil action to recover 1.54 million dollars in cash stolen from her by members of Apostolic United Brethren. At the time Hill was the estranged wife of Harry Hilf, the Godfather of Detroit gambling.

Allred polygamists Dennis Matthews and John Putvin had been retained to purchase the Desert Inn Ranch, the Las Vegas mob's recreational ranch in southern Utah. However, they took the cash, 1.5 million, to their polygamist leader, Owen Allred, where they conspired to maliciously convert the money to their own use.

Llewellyn is an outspoken muckraker of Mormon abuse, a free lance writer and recognized expert on Mormon fundamentalism and polygamy. He was also the lead investigator in a second lawsuit against polygamist leader, James D. Harmston and his True and Living Church, headquartered at Manti, Utah.