In September 1985, when only 16 years old, Oklahoma City resident Sean Sellers shot a convenience store clerk to death. Why? The guy wouldn't sell him any booze, so it seemed like as good a time as any to see "what [murder] felt like." Then, the following March, Sellers killed both his mom and stepfather while they were sleeping and tried to make their bedroom look as if someone other than Sellers himself broke into their house and murdered them.
After his arrest, Sellers told lawyers and jurors that his studies into Satanism led to his soul being possessed by a demon called "Ezurate," and that he'd read Anton Lavey's The Satanic Bible "hundreds of times." In jail, he converted to Christianity and went on several talk shows, including The Oprah Winfrey Show and Geraldo, to discuss the downfalls of devil-worshipping.
On February 4, 1999, Sellers was executed via lethal injection. For his last words, he recited part of the Christian song "Set My Spirit Free": "Set my spirit free that I might praise Thee. Set my spirit free that I might worship Thee."