FILE - This undated file photo provided by the Georgia Department of Corrections shows death row inmate Troy Davis. Georgia's pardons board on Tuesday, Sept. 20, 2011, rejected clemency for Davis despite high-profile support for his claim that he was wrongly convicted of killing MacPhail in 1989. Davis is set to die on Wednesday, Sept. 21. It is the fourth time in four years his execution has been scheduled by Georgia officials. (AP Photo/Georgia Department of Corrections, File)
JACKSON — A Georgia judge has refused to halt the execution of death row inmate Troy Davis after a last-minute appeal by his attorneys.
Davis' attorney Brian Kammer said a Butts County Superior Court judge on Wednesday rejected an appeal by Davis.
Davis is scheduled to die at 7 p.m. EDT on Wednesday for the killing of off-duty Savannah officer Mark MacPhail.
His attorneys filed an appeal earlier in the day challenging ballistics evidence linking Davis to the crime and eyewitness testimony identifying Davis as the shooter. They say the evidence was "egregiously false and misleading."
Prosecutors have stood by their case.
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.
Troy Davis, the condemned inmate who convinced hundreds of thousands of people but not a single court of his innocence, waited to be executed Wednesday as his supporters held vigils outside Georgia's death row and as far away as London and Paris.
His offer to take a polygraph test was rejected. So was his request for the pardons board to give him one more hearing. His attorneys once again challenged the evidence that helped convict him of killing off-duty police officer Mark MacPhail in 1989.
Davis' supporters tried increasingly frenzied measures, urging prison workers to stay home and even posting a judge's phone number online, hoping people will press him to put a stop to the 7 p.m. lethal injection.
"We're trying everything we can do, everything under the law," said Chester Dunham, a civil rights activist and talk show host protesting in Savannah, where MacPhail, 27, was killed.
Outside the Jackson prison that houses Georgia's death row, about 100 people gathered early Wednesday afternoon for a prayer rally. As they shouted, "Free Troy Davis!" a man in a red SUV drove by and shouted, "Kill him!"
About 150 people gathered in support of Davis in Paris, many of them carrying signs emblazoned with his face. "Everyone who looks a little bit at the case knows that there is too much doubt to execute him," Nicolas Krameyer of Amnesty International said at the protest.
Davis' execution has been stopped three times since 2007, but on Wednesday the 42-year-old appeared to be out of legal options.
As his last hours ticked away, an upbeat and prayerful Davis turned down an offer for a special last meal as he met with friends, family and supporters. His attorney Stephen Marsh said Davis would have spent part of that time taking a polygraph test if pardons officials had taken his offer seriously.
"He doesn't want to spend three hours away from his family on what could be the last day of his life if it won't make any difference," Marsh said.
Amnesty International says nearly 1 million people have signed a petition on Davis' behalf. His supporters include former President Jimmy Carter, Pope Benedict XVI, a former FBI director, the NAACP and several conservative figures.
"I'm trying to bring the word to the young people: There is too much doubt," rapper Big Boi, of the Atlanta-based group Outkast, said at a church near the prison.
The U.S. Supreme Court gave Davis an unusual opportunity to prove his innocence in a lower court last year, though the high court itself did not hear the merits of the case.
He was convicted in 1991 of killing MacPhail, who was working as a security guard at the time. MacPhail rushed to the aid of a homeless man who prosecutors said Davis was bashing with a handgun after asking him for a beer. Prosecutors said Davis had a smirk on his face as he shot the officer to death in a Burger King parking lot.
No gun was ever found, but prosecutors say shell casings were linked to an earlier shooting for which Davis was convicted.
Witnesses placed Davis at the crime scene and identified him as the shooter, but several of them have recanted their accounts and some jurors have said they've changed their minds about his guilt. Others have claimed a man who was with Davis that night has told people he actually shot the officer.
"Such incredibly flawed eyewitness testimony should never be the basis for an execution," Marsh said. "To execute someone under these circumstances would be unconscionable."
State and federal courts, however, have repeatedly upheld Davis' conviction. A federal judge dismissed the evidence advanced by Davis' lawyers as "largely smoke and mirrors."
"He has had ample time to prove his innocence," said MacPhail's widow, Joan MacPhail-Harris. "And he is not innocent."
The latest motion filed by Davis' attorneys in Butts County Court disputes testimony from the expert who linked the shell casings to the earlier shooting involving Davis, and challenged testimony from two witnesses. Prosecutors said the filing was a delay tactic that offered nothing the courts hadn't seen before.
The National Association for the Advancement of Colored People, which has helped lead the charge to stop the execution, said it was considering asking President Barack Obama to intervene.
Obama cannot grant Davis clemency for a state conviction. Richard Dieter, executive director of the Death Penalty Information Center, said he could halt the execution by asking for an investigation into a federal issue if one exists.
Dieter considered that prospect unlikely, but dozens of protesters outside the White House called on Obama to step in. "The fact that the White House hasn't addressed this issue is completely disrespectful," college student Talibah Arnett said.
Davis was not the only U.S. inmate scheduled to die Wednesday evening. In Texas, white supremacist gang member Lawrence Russell Brewer was headed to the death chamber for the 1998 dragging death of a black man, James Byrd Jr., one of the most notorious hate crime murders in recent U.S. history.
In Savannah, Davis supporters presented petitions urging the state to spare Davis' life, saying they were signed by 240,000 people. They delivered the petitions to District Attorney Larry Chisolm, though he has said he is powerless to intervene.
Davis' best chance may have come last year, in a hearing ordered by the U.S. Supreme Court. It was the first time in 50 years that justices had considered a request to grant a new trial for a death row inmate.
The high court set a tough standard for Davis to exonerate himself, ruling his attorneys must "clearly establish" Davis' innocence — a higher bar to meet than prosecutors having to prove guilt. After the hearing judge ruled in prosecutors' favor, the justices didn't take up the case.
The planned execution has drawn widespread criticism in Europe, where politicians and activists made last-minute pleas for a stay. A vigil was planned 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. "To carry out this irrevocable act now would be a terrible mistake which could lead to a tragic injustice," said Renate Wohlwend of the council's Parliamentary Assembly.
Spencer Lawton, the district attorney who secured Davis' conviction in 1991, said he was embarrassed for the judicial system — not because of the execution, but because it has taken so long to carry out.
"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."