JACKSON, Ga. (AP) — 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. A judge rejected a last-minute appeal by his attorneys, who have repeatedly but futilely challenged the evidence that helped convict Davis 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. But mostly, they declared “I am Troy Davis” on signs, T-shirts and the Internet, hoping to sway authorities.

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!”

Many of the roughly 150 demonstrators in Paris carried signs emblazoned with Davis’ 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.

“Troy Davis has impacted the world,” said his sister Martina Correia. “They say, ‘I am Troy Davis,’ in languages he can’t speak.”

His attorney Stephen Marsh said Davis would have spent part of Wednesday 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 in Savannah.

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. Superior Court Judge Thomas Wilson rejected the appeal, and prosecutors said the filing was just a delay tactic.

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 that 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.”

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Associated Press reporters Russ Bynum in Savannah, Kate Brumback and Marina Hutchinson in Jackson, Eric Tucker in Washington and Sohrab Monemi in Paris contributed to this report.

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Copyright 2011 The Associated Press.