The Georgia pardons board has rejected a request from condemned inmate Troy Davis to reconsider its decision to spare his life.
The state Pardons and Paroles Board said in a statement Wednesday it would not review its decision to allow the execution to go forward.
Davis is set to die at 7 p.m. for the 1989 killing of off-duty Savannah officer Mark MacPhail, who was slain while rushing to help a homeless man being attacked.
Davis' lawyers have long argued Davis was a victim of mistaken identity. Prosecutors say they have no doubt that they charged the right person with the crime.
Supporters planned vigils outside Georgia's death row prison in Jackson and protests at U.S. embassies in Europe.
Earlier, defense lawyer Stephen Marsh told The Associated Press that the Georgia Department of Corrections denied his request to allow Davis to take a polygraph test. Marsh had said he hoped the polygraph would convince the state pardons board to reconsider a decision against clemency.
After winning three delays since 2007, Davis lost his most realistic chance at last-minute clemency this week when the state pardons board denied his request. He was set to be executed by injection at 7 p.m. Wednesday for the 1989 killing of Mark MacPhail, an off-duty police officer who was working as a security guard in Savannah when he was shot dead rushing to help a homeless man who had been attacked.
Some witnesses who fingered him at trial as the shooter later recanted, and others who did not testify came forward to say another man did it. But a federal judge dismissed those changed and new accounts as "largely smoke and mirrors" after a hearing Davis was granted last year to argue for a new trial, which he did not win.
Davis didn't want a last meal. He planned to spend his final hours meeting with friends, family and supporters.
He has received support from hundreds of thousands of people, including a former FBI director, former President Jimmy Carter and Pope Benedict XVI. Some of his backers resorted to urging prison workers to strike or call in sick Wednesday, and they considered a desperate appeal for White House intervention. And some of Davis' supporters were considering whether to ask President Barack Obama to intervene, a move that legal experts said was unlikely.
In Europe, where the planned execution has drawn widespread criticism, politicians and activists were making a last-minute appeal to the state of Georgia to refrain from executing Davis. Amnesty International and other groups planned a protest outside the U.S. Embassy in Paris later Wednesday and Amnesty also called a vigil outside the U.S. Embassy in London.
Parliamentarians and government ministers from the Council of Europe, the continent's human rights watchdog, called for Davis' sentence to be commuted. Renate Wohlwend of the Council's Parliamentary Assembly said that "to carry out this irrevocable act now would be a terrible mistake which could lead to a tragic injustice."
Prosecutors have no doubt they charged the right person, and MacPhail's family lobbied the pardons board Monday to reject Davis' clemency appeal. The board refused to stop the execution a day later.
"He has had ample time to prove his innocence," said MacPhail's widow, Joan MacPhail-Harris. "And he is not innocent."
Spencer Lawton, the district attorney who secured Davis' conviction in 1991, said he was embarrassed for the judicial system that the execution has taken so long.
"What we have had is a manufactured appearance of doubt which has taken on the quality of legitimate doubt itself. And all of it is exquisitely unfair," said Lawton, who retired as Chatham County's head prosecutor in 2008. "The good news is we live in a civilized society where questions like this are decided based on fact in open and transparent courts of law, and not on street corners."
MacPhail was shot to death Aug. 19, 1989, after coming to the aid of Larry Young, who was pistol-whipped in a Burger King parking lot. Prosecutors say Davis was with another man who was demanding that Young give him a beer when Davis pulled out a handgun and bashed Young with it. When MacPhail arrived to help, they say Davis had a smirk on his face as he shot the officer to death.
Witnesses placed Davis at the crime scene and identified him as the shooter. Shell casings were linked to an earlier shooting that Davis was convicted of. There was no other physical evidence. No blood or DNA tied Davis to the crime and the weapon was never found.
Davis' attorneys say seven of nine key witnesses who testified at his trial have disputed all or parts of their testimony.
The state initially planned to execute him in July 2007 but the pardons board granted him a stay less than 24 hours before he was to die. The U.S. Supreme Court stepped in a year later and halted the lethal injection two hours before he was to be executed. And a federal appeals court halted another planned execution a few months later.
Over the years, Davis has picked up high-profile support from a host of dignitaries and dozens of federal lawmakers. Conservative figures have also advocated on his behalf, including former U.S. Rep. Bob Barr, ex-Justice Department official Larry Thompson and one-time FBI Director William Sessions.
The U.S. Supreme Court granted Davis a hearing to prove his innocence, the first time it had done so for a death row inmate in at least 50 years. At that June 2010 hearing, two witnesses testified that they falsely incriminated Davis at his trial when they said Davis confessed to the killing. Two others told the judge the man with Davis that night later said he shot MacPhail.
Prosecutors, though, argued that Davis' lawyers were simply rehashing old testimony that had already been rejected by a jury. And they said no trial court could ever consider the hearsay from the other witnesses who blamed the other man for the crime.
U.S. District Judge William T. Moore Jr. sided with them. He said the evidence presented at the hearing wasn't nearly enough to prove Davis is innocent and validate his request for a new trial. He said while Davis' "new evidence casts some additional, minimal doubt on his conviction, it is largely smoke and mirrors."