The last man to be executed during George W Bush's term as governor of Texas was sentenced to death on the basis of a single piece of evidence – one human hair – which did not actually belong to him, DNA tests have shown.
Claude Howard Jones was convicted in 1990 of murdering an off-licence owner and was put to death by lethal injection 10 years later. He suffered the ultimate penalty because jurors were informed that a strand of his hair had been found on the floor close to the victim's body.
That now turns out to be untrue: laboratory analysis of the crucial item of evidence has revealed that it actually came from the head of the store's owner, Allen Hilzendager.
"My father never claimed to be a saint, but he always maintained that he didn't commit this murder," Jones's son, Duane, said yesterday. "I hope these results will serve as a wake-up call ... Serious problems exist in the criminal justice system that must be fixed if our society is to continue using the death penalty."
This week's discovery has huge legal significance because there has previously been no clear-cut case in modern US history of a defendant being sentenced to death on the back of evidence which is demonstrably false.
It does not necessarily prove that Jones, who was 60 at the time of his death, was innocent of murder. But it does add weight his claim that he was waiting in a car outside the liquor store on the afternoon of 14 November 1989 when an accomplice, Kerry Daniel Dixon, walked in and shot Hilzendager.
The men, both career criminals, planned to steal the till, which contained several hundred dollars in cash, from the off-licence at Point Blank, 80 miles east of Houston. Witnesses said they saw one man walk into the store to commit the crime while the other stayed behind to act as getaway driver.
Without the hair from the scene, Jones would have received life imprisonment, since under Texas law it is impossible to secure a death penalty conviction without corroborating physical evidence that the suspect was directly responsible for a crime such as murder.
None of the witnesses was able to positively identify which of the two men had walked into the store and pulled the trigger. A third accomplice, Timothy Jordan, who supplied the fatal weapon, testified that Jones had confessed to the killing, but later withdrew his evidence, saying he had embellished it to secure a lighter sentence.
For the original trial in 1990, analysis of the hair was carried out under a microscope, a technique now obsolete because it is thought to be unreliable. By the time Jones was executed a decade later, DNA testing was relatively commonplace, but his attorneys were unable to convince any court in Texas to have the crucial hair reviewed.
In 2000, just before Jones was killed, Mr Bush declined a request to order a stay of execution. The Texas Observer magazine, which carried out this week's DNA test, claimed that state attorneys "failed to inform him that DNA evidence might exonerate Jones".
The former US president, who is on the road this week publicising his memoirs, has declined to comment. Although he signed 151 execution orders – more than any other governor – during his time in office, Bush has previously stated his support for DNA testing as a means to confirm a suspect's guilt.
In the years after his execution, Jones's family tried repeatedly to get access to the hair sample, but their requests to have it DNA tested were blocked by the local district attorney, who attempted to have it destroyed. It was only released after the Texas Observer resorted to filing a lawsuit demanding access to the item.
That kind of obstruction is true to form in Texas, which has executed 464 people since the death penalty was re-introduced to the US more than three decades ago, giving it one of the world's busiest death rows outside Saudi Arabia and China.
Earlier this year, doubt was cast on the conviction of Cameron Todd Willingham, who was was put to death in 2004 after being convicted of starting a fire in 1991 that killed his three daughters. Several experts have claimed that he was completely innocent and that prosecutors obscured crucial evidence.
An official report into Willingham's case by the Texas Forensic Science Commission will not be completed until next year. Its release was delayed by the current Governor of Texas, Rick Perry, who last October removed three members of the panel that is writing the report and replaced them with people thought to be more supportive of capital punishment.