"This issue of executing juveniles has been controversial. It's controversial in the international forum, and the U.S. stands alone in insisting on these executions," said Richard Deiter, executive director of the National Death Penalty Information Center, an anti-capital punishment organization in Washington, D.C. "It's been 40 years since we crossed that line."
Sellers was 16 years old when he killed. The last time anyone died for crimes committed at that age was April 10, 1959, when Maryland executed Leonard M. Shockley. Since the death penalty was reinstated in 1976, Deiter said, 12 people have been put to death for crimes committed at age 17.
Nationwide, death rows now hold 16 offenders who murdered when they were 16 years old and 54 more who committed their crimes at age 17.
Age will be an issue when Sellers goes before the Oklahoma Pardon and Parole Board for a clemency hearing Wednesday.
His supporters say he shouldn't die for crimes committed as a teen. They also point to a diagnosis of multiple personality disorder made after Sellers' conviction.
His attorney, Steve Presson, plans to base much of his argument on the multiple personality diagnosis but agrees "the age issue is relevant here."
"We all look for why something happened, and a 16-year-old boy ravaged with multiple personality disorder who was a good student at school and inexplicably committed these crimes... Something went wrong."
Sellers, now a Christian involved in outreach ministries from his death row cell, once worshipped the occult. At his trial, the defense said Sellers was addicted to the game "Dungeons & Dragons" and it dictated his actions.
Police Detective Ron Mitchell said a satanic bible, altar, writings and drawings were found in Sellers' bedroom.
In the 23 years since the Supreme Court restored capital punishment, the Oklahoma parole board has never recommended clemency. Any such recommendation in this case would have to be approved by Gov. Frank Keating, who supports the death penalty.
Attorney General Drew Edmondson's office will argue against clemency. He said Sellers' age vs. sentence had already been weighed. "The age of the defendant is properly something the jury should take into account when deciding the death penalty," he said. "The place for different treatment was at the trial. A good number of young people commit homicides that are not given the death penalty."
Curiously, another Oklahoma case helped shape the Supreme Court decisions that set 16 as the minimum age at which defendants can be condemned. William Wayne Thompson was 15 in January 1983 when he helped beat and shoot to death his allegedly abusive former brother-in-law, whose body was dumped into the Washita River in southwestern Oklahoma. Thompson was sentenced to die.
The high court overturned the sentence in 1988, declaring the execution of a 15-year-old unconstitutional. Justices concluded, "It would offend civilized standards of decency to execute a person who was less than 16 years old at the time of his or her offense." Thompson's sentence was commuted to life in prison. Sellers was four months past his 16th birthday when he and a friend stopped at an Oklahoma City convenience store Sept. 8, 1985. Displaying a handgun taken from his friend's grandfather's house, Sellers told his companion, "I want to see what it feels like to kill somebody."
Inside, 32-year-old clerk Robert Bower was raising a cup of coffee to his lips when he was shot once, then again.
Six months passed as police exhausted lead after lead in searching for Bower's killer.
On March 5, 1986, Sellers killed again. This time, the targets were his mother, Vonda Bellofatto, 32, and stepfather, Paul Bellofatto, 43.
Dressed only in his underwear, Sellers crept into their bedroom after midnight. He shot his stepfather in the head with Bellofatto's .44-caliber Magnum revolver, then shot his mother. As Mrs. Bellofatto rose slightly, he shot her again.
The next morning, he staged discovering the bodies. When police arrived, Sellers was waiting with the friend who's been with him at the convenience store. The same morning, police got a call from a 13-year-old who said she'd heard Sellers had stabbed the clerk in September. They initially dismissed the information because Bower had been shot. But as they drove the friend home, detectives mentioned the convenience store homicide and a possible link to Sellers.
"To our shock," Mitchell said, the friend acknowledged he had been there and that Sellers had killed Bower.
Edmondson said the gap between the slayings likely went against Sellers.
"Without doubt, they weighed against his age the fact that he committed multiple murders a distance apart in time," the district attorney said. "So he had an opportunity to reflect on the murder of the store clerk for weeks before he murdered his mother and stepfather."
Sellers refused to talk to police after calling them to report his parents' murders. But in recent years, on a run by supporters, he has apologized for his crimes and written that he doesn't know what motivated him to kill.
One Website article was entitled "My Confession."
"I promptly made a copy of it and stuck it in our file," Mitchell said. "At least we have a confession in our file."