From left, Anneliese MacPhail, mother of slain off-duty officer Mark MacPhail, MacPhail's son Mark Jr, wife Joan and daughter Madison, speak out after a Georgia Board of Pardons and Paroles hearing for convicted killer Troy Davis.

Supporters of Georgia death row inmate Troy Davis react after word spread that the US Supreme Court needed more time to hear a plea from Davis.

An anti-death penalty protester is helped off the ground after hearing about a delay of the execution by the US Supreme Court for Georgia death row inmate Troy Davis.

Law enforcement line up in front of supporters of convicted killer Davis after some activists became rowdy at the Georgia Diagnostic and Classification prison in Jackson.

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.

Supporters of convicted killer Davis hug and cry after a last minute US Supreme Court appeal was denied.

Georgia has executed Troy Davis for the murder of an off-duty police officer, a crime he denied committing right to the end.

Supporters around the world mourned and declared that an innocent man was put to death.

Defiant to the end, he told relatives of Mark MacPhail that his 1989 slaying was not his fault.

Reuters NOT WITHOUT A FIGHT: Protesters show their support for death row inmate Troy Davis during a rally in Atlanta. A parole board in Georgia has denied a last-ditch clemency appeal by Davis.

"I did not have a gun," he insisted.

"For those about to take my life," he told prison officials, "may God have mercy on your souls. May God bless your souls."

Davis was declared dead at 11.08 (3.08pm NZ time). The lethal injection began about 15 minutes earlier, after the Supreme Court rejected an 11th-hour request for a stay.

AP DEATH PENALTY: An undated file photo of death row inmate Troy Davis.

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.

It did nothing to stop the execution of white supremacist gang member Lawrence Russell Brewer, however. He was executed today, NZ time, for the infamous dragging death slaying of James Byrd Jr, a black man from East Texas.

Though Davis' attorneys said seven of nine key witnesses against him disputed all or parts of their testimony, state and federal judges repeatedly ruled against granting him a new trial. As the court losses piled up Wednesday, his offer to take a polygraph test was rejected and the pardons board refused to give him one more hearing.

"They say death row; we say hell no!" protesters shouted outside the Jackson prison where Davis was to be 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 would be "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.

About 10 counter-demonstrators also were outside the prison, showing support for the death penalty and the family of Mark MacPhail, the man Davis was convicted of killing in 1989. MacPhail's son and brother attended the execution.

"He had all the chances in the world," his mother, Anneliese MacPhail, said of Davis in a telephone interview. "It has got to come to an end."

At a Paris rally, many of the roughly 150 demonstrators 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.

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," his sister Martina Correia said at a news conference. "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 signed a petition on Davis' behalf, including more than 800 from New Zealand. His supporters included 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.

"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 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."

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

The National Association for the Advancement of Colored People, which helped lead the charge to stop the execution, said it considered asking Obama to intervene, even though he cannot grant Davis clemency for a state conviction.

Press secretary Jay Carney issued a statement saying that although Obama "has worked to ensure accuracy and fairness in the criminal justice system," it was not appropriate for him "to weigh in on specific cases like this one, which is a state prosecution."

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 took 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 civilised society where questions like this are decided based on fact in open and transparent courts of law, and not on street corners."

WHITE SUPREMACIST EXECUTED FOR TEXAS DRAGGING

White supremacist gang member Lawrence Russell Brewer has been executed for the infamous dragging death slaying of James Byrd Jr, a black man from East Texas.

Byrd, 49, was chained to the back of a pickup truck and pulled whip-like to his death along a bumpy asphalt road in one of the most grisly hate crime murders in recent Texas history.

Brewer, 44, was asked if he had any final words, to which he replied: "No. I have no final statement."

He glanced at his parents watching through a nearby window, took several deep breaths and closed his eyes. A single tear hung on the edge of his right eye as he was pronounced dead at 6.21pm, 10 minutes after the lethal drugs began flowing into his arms, both covered with intricate black tattoos.

Byrd's sisters also were among the witnesses in an adjacent room.

"Hopefully, today's execution of Brewer can remind all of us that racial hatred and prejudice leads to terrible consequence for the victim, the victim's family, for the perpetrator and for the perpetrator's family," Clara Taylor, one of Byrd's sisters, said.

She called the punishment "a step in the right direction".

"We're making progress," Taylor said. "I know he was guilty so I have no qualms about the death penalty."

Appeals to the courts for Brewer were exhausted and no last-day attempts to save his life were filed.

Besides Brewer, John William King, now 36, also was convicted of capital murder and sent to death row for Byrd's death, which shocked the nation for its brutality. King's conviction and death sentence remain under appeal. A third man, Shawn Berry, 36, received a life prison term.

"One down and one to go," Billy Rowles, the retired Jasper County sheriff who first investigated the horrific scene, said. "That's kind of cruel but that's reality."

It was about 2.30am on Sunday, June 7, 1998, when witnesses saw Byrd walking on a road not far from his home in Jasper, a town of more than 7000 and about 125 miles northeast of Houston. Many folks knew he lived off disability cheques, couldn't afford his own car and walked where he needed to go. Another witness then saw him riding in the bed of a dark pickup.

Six hours later and some 10 miles away on Huff Creek Road, the bloody mess found after daybreak was thought at first to be animal road kill. Rowles, a former Texas state trooper who had taken office as sheriff the previous year, believed it was a hit-and-run fatality but evidence didn't match up with someone caught beneath a vehicle. Body parts were scattered and the blood trail began with footprints at what appeared to be the scene of a scuffle.

"I didn't go down that road too far before I knew this was going to be a bad deal," he said at Brewer's trial.

Fingerprints taken from the headless torso identified the victim as Byrd.

Testimony showed the three men and Byrd drove out into the county about 10 miles and stopped along an isolated logging road. A fight broke out and the outnumbered Byrd was tied to the truck bumper with a 24 1/2-foot logging chain. Three miles later, what was left of his shredded remains was dumped between a black church and cemetery where the pavement ended on the remote road.

Brewer, King and Berry were in custody by the end of the next day.

The crime put Jasper under a national spotlight and lured the likes of the Ku Klux Klan and the Black Panthers, among others, to try to exploit the notoriety of the case which continues - many say unfairly - to brand Jasper more than a decade later.

King was tried first, in Jasper. Brewer's trial was moved 150 miles away to Bryan. Berry was tried back in Jasper. DNA showed Byrd's blood on all three of them.

Brewer was from Sulphur Springs, about 180 miles to the northwest, and had been convicted of cocaine possession. He met King, a convicted burglar from Jasper, in a Texas prison where they got involved in a KKK splinter group known as the Confederate Knights of America and adorned themselves with racist tattoos. Evidence showed Brewer had violated parole and was involved in a number of burglaries and thefts in the Jasper area.

King had become friends with Berry and moved into Berry's place. Evidence showed Brewer came to Jasper to stay with them.

