Georgia executed Troy Davis on Wednesday night for the murder of an off-duty police officer, a crime he denied committing right to the end as supporters around the world mourned and declared that an innocent man was put to death.

As he lay strapped to a gurney in the death chamber, Davis told relatives of Mark MacPhail that he was not responsible for his 1989 slaying. "I did not have a gun," he insisted.

"All I can ask ... is that you look deeper into this case so that you really can finally see the truth," he said.

He asked his friends and family to "continue to fight this fight." Of prison officials he said, "may God have mercy on your souls. May God bless your souls."

Davis was declared dead at 11:08 p.m. The lethal injection began about 15 minutes earlier, after the Supreme Court rejected an 11th-hour request for a stay. The court did not comment on its order, which came about four hours after it received the request and more than three hours after the planned execution time.

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Hundreds of thousands of people signed petitions on Davis' behalf, and prominent supporters included an ex-president and an ex-FBI director, liberals and conservatives. His attorneys said seven of nine key witnesses against him disputed all or parts of their testimony, but state and federal judges repeatedly ruled against him — three times on Wednesday alone.

'Nothing to rejoice'

MacPhail's widow, Joan MacPhail-Harris, said there was "nothing to rejoice," but that it was "a time for healing for all families.

"I will grieve for the Davis family because now they're going to understand our pain and our hurt," she said in a telephone interview from Jackson. "My prayers go out to them. I have been praying for them all these years. And I pray there will be some peace along the way for them."

Davis' supporters staged vigils in the U.S. and Europe, declaring "I am Troy Davis" on signs, T-shirts and the internet. Some 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 lethal injection.

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Troy Davis was pronounced dead at 11:08 p.m. Wednesday. ((Georgia Department of Corrections/Reuters))

President Barack Obama deflected calls for him to get involved.

"They say death row; we say hell no!" protesters shouted outside the Jackson prison before Davis was executed. In Washington, a crowd outside the Supreme Court yelled the same chant.

As many as 700 demonstrators gathered outside the prison as a few dozen riot police stood watch, but the crowd thinned as the night wore on and the outcome became clear. The scene turned eerily quiet as word of the high court's decision spread, with demonstrators hugging, crying, praying, holding candles and gathering around Davis' family.

Laura Moye of Amnesty International said the execution was "the best argument for abolishing the death penalty."

"The state of Georgia is about to demonstrate why government can't be trusted with the power over life and death," she said before Davis was put to death.

About 10 counter demonstrators also were outside the prison, showing support for the death penalty and MacPhail's family.

Members of Davis' family who witnessed the execution left without talking to reporters. MacPhail's son and brother also attended.

"I'm kind of numb. I can't believe that it's really happened," MacPhail's mother, Anneliese MacPhail, said in a telephone interview from her home in Columbus, Ga. "All the feelings of relief and peace I've been waiting for all these years, they will come later. I certainly do want some peace."

Of Davis' claims of innocence, she said, "He's been telling himself that for 22 years. You know how it is, he can talk himself into anything."

Davis' execution had been stopped three times since 2007, but on Wednesday the 42-year-old ran out of legal options. The pardons board rejected him, and Georgia's governor does not have the power to grant condemned inmates clemency. 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.

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Anneliese MacPhail, left to right, mother of slain off-duty Savannah police officer Mark MacPhail, MacPhail's son Mark MacPhail, Jr., wife Joan MacPhail and daughter Madison MacPhail, attended a Georgia Board of Pardons and Paroles hearing for Troy Davis on Monday. MacPhail's family said they urged the board to deny his clemency petition and carry out the jury's verdict. ((David Tulis/Associated Press) )

His attorney Stephen Marsh said Davis would have spent part of Wednesday taking a polygraph test if pardons officials had taken his offer seriously.

"Troy Davis has impacted the world," his sister Martina Correia said at a news conference. "They say, 'I am Troy Davis,' in languages he can't speak."

Davis' supporters include former President Jimmy Carter, Pope Benedict XVI, a former FBI director, the NAACP, several conservative figures and many celebrities, including hip-hop star Sean "P. Diddy" Combs.

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.

Convicted of killing off-duty police officer

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.

State and federal courts, however, have repeatedly upheld Davis' conviction. One federal judge dismissed the evidence advanced by Davis' lawyers as "largely smoke and mirrors."

"He has had ample time to prove his innocence," MacPhail-Harris said. "And he is not innocent."

The last motion filed by Davis' attorneys in Butts County Court challenged testimony from two witnesses and disputed testimony from the expert who linked the shell casings to the earlier shooting involving Davis. Superior Court Judge Thomas Wilson and the Georgia Supreme Court rejected the appeal, and prosecutors said the filing was just a delay tactic.