Minister Lynn Hopkins (left) comforts her partner Carolyn Bond after hearing that the US Supreme Court rejected a last minute plea of Georgia death row inmate Troy Davis in Jackson, Georgia, on Wednesday. Davis was executed for killing off-duty Savannah officer Mark MacPhail. Stephen Morton / Associated Press

JACKSON, Georgia - The US state of Georgia executed a man 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 on Wednesday night, 42-year-old Troy 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.

Davis was declared dead at 11:08 pm. The lethal injection began about 15 minutes earlier, after the Supreme Court rejected an 11th-hour request for a stay.

"Justice has been served for Officer Mark MacPhail and his family," State Attorney General Sam Olens said in a statement.

The high 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.

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.

Davis' supporters include former president Jimmy Carter, Pope Benedict XVI, a former FBI director, the National Association for the Advancement of Colored People, several conservative figures and many celebrities, including hip-hop star Sean "P. Diddy" Combs.

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. "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 United States 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. US 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.

About 10 counterdemonstrators 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.

Davis' execution had been stopped three times since 2007, but on Wednesday he 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 friends, family and supporters.

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.

At a Paris rally, many of the roughly 150 demonstrators carried signs emblazoned with Davis' face.

The US 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. One federal judge dismissed the evidence advanced by Davis' lawyers as "largely smoke and mirrors".

Associated Press