Born in 1969, Sellers was 18 months old when his parents divorced. A year later, in 1972, he was left with relatives while his mother hit the road, seeking work. By 1976, she had remarried - to auto mechanic Paul Bellofatto - but they still traveled widely on jobs, and young Sean spent most of his time with aunts and uncles, developing a painful sense of rejection along the way. By age 12, he was actively studying Satanism, immersed in the dark fantasy world of "Dungeons and Dragons." Frequent moves increased his sense of isolation, and a 1983 reunion with his mother and stepfather scarcely improved matters. Dumped with an aunt at Okmulgee, Oklahoma, in March 1984, Sellers plunged deeper into his occult studies, drinking the blood of fellow teenage cultists and using it to write his own personal "dedication to Satan."

Sean's family was reunited in the fall of 1984, in Oklahoma City, but the brooding 15-year-old was already over the edge. In February 1985, Sellers used his own blood to write: "I renounce God, I renounce Christ. I will serve only Satan... Hail Satan." Discovery of his occult interests led to angry scenes with Paul Bellofatto, Setups step-father telling the troubled boy, "You don't exist!"

On September 8, 1985, Sellers and another teenage Satanist invaded a local convenience store, Sean fatally shooting a clerk - Richard Bower - who had once refused to sell them beer. In his own words, the murder "opened a new portal" for Sellers, and he "plunged into Satanism with everything I had."

A few months later, in the middle of the night, he crept into the master bedroom of his Emily home, executing his mother and Bellofatto with his stepfather's own pistol. Sellers contrived to "find" the bodies next day, but his friends were suspicious, and his accomplice in the Bower homicide eventually turned state's evidence to save himself. Convicted on three counts of murder in September 1986, Sellers was sentenced to die, becoming the youngest inmate on Oklahoma's death row.