FILE - This undated file photo provided by the Georgia Department of Corrections shows death row inmate Troy Davis. Georgia corrections officials have set a Sept. 21, 2011, execution date for Davis, for the 1989 murder of Savannah police officer Mark MacPhail. Davis has drawn a considerable amount of worldwide support, from the Vatican to the European Union, from President Jimmy Carter to Pope Benedict XVI. The NAACP has launched an "I am Troy" campaign, and a Change.org petition asking the five-member Georgia pardons board to spare his life has attracted more than 100,000 signatures. (AP Photo/Georgia Department of Corrections, File)
ATLANTA-- Hundreds of thousands of people are rallying behind Georgia death row inmate Troy Davis -- not just because they oppose capital punishment but because they believe the state could put an innocent man to death.
The case is fraught with drama: The murder of an off-duty police officer. Conflicting eyewitness testimony. Last-minute court decisions sparing a condemned man's life and global dignitaries who say they fear an innocent man could die.
Davis has captured considerable attention because of the doubt raised over whether he killed Mark MacPhail in Savannah in 1989. The U.S. Supreme Court even 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, but he couldn't convince a judge to grant him a new trial.
The officer's family believes there's no doubt that Davis killed MacPhail and prosecutors say the right man was convicted.
Davis is scheduled to die Wednesday, the fourth time his execution has been set in four years. He once came within two hours of being put to death. His attorneys say his legal appeals are exhausted and the chances of him winning another reprieve have dwindled.
Still, supporters hope to convince Georgia's pardons board next week to spare his life.
Executing Davis "risks taking the life of an innocent man and would be a grave miscarriage of justice," said former President Jimmy Carter, a Democrat from Georgia and death penalty opponent who wrote a letter on Davis' behalf.
"We believe that in this particular case there's enough evidence to the contrary to prevent this execution from taking place," Carter said Tuesday.
MacPhail was working a late-night shift as a security guard on Aug. 19, 1989, when he saw a homeless man who had been pistol-whipped at a nearby Burger King parking lot. He rushed to help.
Moments after MacPhail approached Davis and two other men, he was shot in the face and the chest. He died before help arrived.
Witnesses identified Davis as the shooter and shell casings were linked to an earlier shooting Davis was convicted of. There was no other physical evidence. No blood or DNA tied Davis to the crime, the weapon was never located and several witnesses who testified at his 1991 trial have disputed all or parts of their testimony.
One of them, Harriet Murray, told the jury she saw Davis pistol-whip her friend. She identified him as MacPhail's killer in a police photo lineup and later pointed to him as the shooter in court, saying he was smirking when he pulled the trigger.
But 11 years later, Murray gave defense attorneys a more vague account of the shooting and didn't name Davis as the killer. Others who did not testify at the trial have since said another man admitted shooting MacPhail.
Prosecutors say many of the concerns about the witness testimony were raised during the trial, and allegations that someone else later confessed are inconsistent and inadmissible in court.
Those questions compelled anti-death penalty groups to get involved. Amnesty International, a human rights organization, started its campaign in February 2007. It printed a report looking at the case and sent it to thousands of members across the globe.
"It took a lot of work for us to break through the noise, and to be serious about the questions of doubt and innocence," said Laura Moye of Amnesty International.
The group inspired Gautam Narula, a University of Georgia student, to fight for Davis' life. Narula plans to attend a rally on Davis' behalf in Atlanta on Friday.
"If it's true that Davis is innocent, this is something that could happen to anyone," said Narula, who has also visited Davis on death row. "Someone was sentenced to death for being at the wrong place at the wrong time. And that means that anyone could be Troy Davis. It happened to be him and it could happen to any of us."
That's the message of the NAACP's "I am Troy" campaign. More than 100,000 people have signed an online petition asking the five-member Georgia pardons board to spare his life. On Thursday, advocacy groups handed over to the board thousands of petitions with the names of more than 660,000 people who support Davis.
Big-name supporters began advocating for Davis in 2007. Pope Benedict XVI's U.S. envoy sent a letter pleading for his life, and Nobel laureate Desmond Tutu urged the courts to review his case. The Rev. Al Sharpton visited him on death row, and plans to return to Atlanta Friday to help lead a rally to support Davis.
Conservative figures also got involved. Former Deputy Attorney General Larry Thompson, who served under President George W. Bush, urged the pardons board to grant Davis clemency because "it is clear now that the doubts plaguing his case can never be adequately addressed." And former U.S. Rep. Bob Barr said in a letter that "even for death penalty supporters such as myself, the level of doubt inherent in this case is troubling."
A group of 27 former judges and prosecutors, including Barr, Thompson and one-time FBI Director William Sessions, asked the U.S. Supreme Court in 2009 for the rare innocence hearing to "prevent a potential miscarriage of justice."
The high court granted the hearing, a momentous decision because death penalty appeals typically look only at questions of procedure and constitutional violations, not guilt or innocence.
During two days of testimony in June 2010, U.S. District Judge William T. Moore Jr. heard from two witnesses who said they falsely incriminated Davis and two others who said another man had confessed to being MacPhail's killer in the years since Davis' trial.
Moore said the evidence cast some additional doubt on Davis' conviction, but that it was "largely smoke and mirrors" and not enough to vindicate Davis or grant him a new trial.
Some of MacPhail's family members blame the advocacy groups for drumming up the worldwide interest.
"I just think they should stay away. They don't know the case, they're just running their mouths," said Anneliese MacPhail, the slain officer's mother. "It's none of their business. They don't know all the circumstances."
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