Their victim was 15 when she died.
They snatched her from the street in front of her Kansas City house, raped her and ignored her pleas for mercy before plunging knives into her throat and chest.
For those crimes committed 23 years ago, the state of Missouri says that they must die.
Yet while the death of Ann Harrison was cruel and unusual, the U.S. Constitution mandates that the deaths of her convicted killers must not be.
And the fact that Roderick Nunley and Michael Taylor still are alive reflects the long-standing national struggle over how to mete out society's most extreme punishment.
Even widespread use of lethal injection as an alternative to methods such as the gas chamber, the gallows or electrocution provided only a humane veneer to what essentially is an inhumane act: the taking of another person's life.
Some death-penalty experts, both pro and con, even argue that the firing squad's bullet to the heart is as quick and pain-free as any other killing method.
"Any manner of killing someone," Deborah Denno, a law professor at Fordham University in New York, "is going to involve some kind of pain."
The constitutional question is what level of pain is acceptable before it morphs into "cruel and unusual."
That has clogged the courts and delayed for years executions for convicted killers such as Nunley and Taylor.
"It's wrong to equate humane with painless," said New York Law School professor Robert Blecker. "Some people deserve a quick but painful death."
Today, that ongoing debate centers squarely on Missouri.
Nunley and Taylor are among 21 death-row inmates challenging the state's newly adopted method for executions with a single drug that never has been used -- anywhere -- to carry out a death sentence.
Last week, the Missouri Supreme Court declined to set execution dates for six death-row inmates until the legal dispute over the state's execution method can be resolved.
A shortage of sodium thiopental, the first part of the three-drug execution method, prompted Missouri's adoption of the untried drug propofol, and officials in other states facing the same shortage are keenly interested in what happens here.
"There's no escaping the fact," said Richard Dieter, executive director of theDeath Penalty Information Centerin Washington, D.C. "This is an experiment with a human subject."
The execution protocol the Missouri Department of Corrections adopted in May calls for the injection of propofol, an anesthetic widely used in surgical procedures.
Although the drug is administered in a carefully controlled and monitored way in a medical setting, in the execution process it will be injected in one massive dose that will guarantee death.
Attorneys for the 21 Missouri death-row inmates maintain that it also will be painful. They cite medical experts documenting surgical patients reporting pain from the drug before losing consciousness.
"The protocol violates both constitutions (the U.S. and Missouri) by creating an unprecedented, substantial likelihood of foreseeable infliction of excruciating pain in the course of executing the plaintiffs," they argue in the case pending in Cole County Circuit Court.
The state counters that the U.S. Supreme Court has ruled that it is not necessary for execution to be completely painless for it to be constitutional. The state's lawyers also argue that the plaintiffs must show an alternative to the method they claim is unconstitutional.
The state's attorneys quote the U.S. Supreme Court on that point: "Not only must there be an alternative, it must effectively address a substantial risk of serious harm." The alternative must be "feasible, readily implemented and in fact, significantly reduce a substantial risk of severe pain."
While Denno opposes the death penalty and Blecker advocates it, the two professors share the belief that there is a feasible alternative.
"We agree that if you're going to have the death penalty, probably the most appropriate method is the firing squad," Blecker said.
The state of Utah has carried out three executions by firing squad since 1977, most recently in 2010, and Denno said in none of those cases was any undue suffering reported.
"It's probably as painless a method as we have," she said.
Denno also sees it as a more honest approach to carrying out a death sentence.
"You can't have it both ways," she said. "You can't execute people while pretending that they're just falling asleep."
For Blecker, one of the most galling aspects of execution by lethal injection is the resemblance to a medical setting. He made a critique on that point in his essay "Killing Them Softly: Meditations on a Painful Punishment of Death."
"The condemned dies in a gurney, wrapped in white sheets with an IV in his veins, surrounded by his closest kin, monitored by sophisticated medical devices," he wrote. "How we kill those we rightly detest should in no way resemble how we kill or euthanize beloved parents or pets."
Although two of the nation's most prominent legal voices in the realm of capital punishment agree on the use of firing squads, Dieter, of the Death Penalty Information Center, doesn't foresee a rush by the states to embrace it or any other previously used methods.
"We haven't seen any serious attempts to go back," he said.
That's partly, he said, because of the squeamishness of a public that's become accustomed to an "orderly, antiseptic and bloodless" process.
Historically, each new execution method has been promoted with an eye toward completing the task in a more humane way.
Missouri's attempt to carry out executions with an untried drug, however, is driven more by necessity than a desire to lessen the suffering of the condemned, the experts say.
"It's never been acceptable under the Eighth Amendment to use something," Denno said, "just because nothing else is available."