Davis, 42, who had continued to maintain his innocence, died shortly after 1pm today (AEST) after desperate efforts by his defence team failed to win a stay. He died at 11.08am, Georgia time. This undated handout image from the Georgia Department of Corrections shows death row inmate Troy Davis. Credit:Reuters As he lay awaiting the injection, Davis turned to the son and brother of the dead officer, telling them that he was not responsible for his death, according to reporters. He then turned to his own family and friends and urged them to continue the fight to clear his name. Finally, Davis addressed prison officers saying: "May God have mercy on your souls." His death was marked by last-minute drama when Georgia officials delayed the execution by an excruciating three-and-a-half hours as they awaited a final ruling by the US Supreme Court.

Davis had been about to be strapped to a gurney to be injected, as state witnesses assembled to view his execution, when the schedule was interrupted. But the court ultimately denied him a reprieve. Hundreds of supporters gathered outside the jail in Jackson, about 60 kilometres south-east of Atlanta, fell into despair once the decision was known. There was a huge police presence to quell any eruption of anger. The nation’s highest court was Davis’s last chance after Georgia’s judiciary rejected last-minute appeals from his defence team earlier in the day. It was the fourth time that an execution date had been set for Davis, who was convicted of the 1989 shooting of 27-year-old policeman Mark MacPhail. The off-duty officer was shot in the chest and face when he sought to intervene in an argument in the car park of a Savannah takeaway. Three stays had been granted since 2007, with Davis on one occasion coming within two-and-a-half hours of being executed.

The extraordinary legal case has put America’s death penalty in an uncomfortable spotlight, with hundreds of thousands of people worldwide, including some from Australia, pleading for clemency in the wake of a series of court appeals and with seven of nine witnesses having recanted their original testimony, some claiming to have been coerced by police. No weapon, DNA evidence or surveillance footage was found to link Davis to the crime. His defence team pointed the finger at a second man who had been with Davis on that evening and who later became the prosecution’s star witness. Petitioners had included Pope Benedict, Nobel Peace Laureates Jimmy Carter and Archbishop Desmond Tutu, a former FBI director and at least 40 members of the US Congress. Davis’s advocates had included Amnesty International and the National Association for the Advancement of Coloured People, as well as the Innocence Project, which has helped exonerate 17 death row inmates through DNA testing. A New York Times editorial called the execution “a grievous wrong”. It said the failure of Georgia’s Pardon and Parole Board to grant clemency was “appalling in the light of developments after [Davis’s] conviction”. “Across the country, the legal process for the death penalty has shown itself to be discriminatory, unjust and incapable of being fixed.”

Davis had spent Wednesday saying goodbye to about 25 visitors before refusing a last meal. He also spent time praying with his local pastor, who described the delay in his execution as “a human rights violation” and “a cruel and unusual punishment”. Speaking through a lawyer on Tuesday, he said: “I will not stop fighting before I’ve taken my last breath. Georgia is prepared to snuff out the life of an innocent man.” Davis’s defence team had sought a polygraph, or lie detector, test for their client before his scheduled execution in a bid to win a further stay, but that had been denied by prison officials. Their last appeals to the judicial system were denied successively by the state’s Superior Court and Supreme Court, and finally by the highest court in the US. Supporters rallying outside the jail were briefly encouraged when word came that the Supreme Court had delayed the execution just minutes ahead of its scheduled start at 9am. But it quickly emerged that the delay was only temporary, while the court’s nine justices considered whether to issue a stay.

Under Georgia law, the state governor does not have the power to intervene. That power is delegated to the parole board, which on Tuesday ruled that the execution could proceed. “The board has considered the totality of the information presented in this case and thoroughly deliberated on it, after which the decision was to deny clemency,” the board’s statement read. Prosecutors and MacPhail’s widow and mother all said they had no doubt about Davis’s guilt and that the right man was being punished. “I’m hoping that this is the end for our family,” said widow Joan MacPhail ahead of the execution. “We want to believe so desperately that this is it.” The dead policeman’s mother, Anneliese MacPhail, said: “I will never have closure because that can’t be. But I may have some peace which I hope for. I certainly need it.”

Spencer Lawton, the retired prosecutor in the case, told CNN: “There is the legal case, the case in court, and the public relations case. We have consistently won the case as it has been presented in court. We have consistently lost the case as it has been presented in the public realm, on TV and elsewhere.” Loading Davis became the fourth person executed in Georgia this year and the 34th across the 34 states that retain the death penalty. Texas accounts for a third of executions. However, America’s execution rate has been declining since the death penalty was re-introduced in the mid-1970s. Follow The Age on Twitter @The Age