ATLANTA (Reuters) - A Georgia parole board on Tuesday denied a last-ditch clemency appeal by Troy Davis, who is set to be executed in a high-profile case on Wednesday for the murder of a police officer.
Davis' case has attracted international attention and became a focus for death penalty opponents because seven of nine trial witnesses have since recanted their testimony, prompting supporters to say he may be innocent.
But two legal experts said Tuesday's decision by Georgia's Board of Pardons and Paroles closes the most viable legal avenue for Davis in his bid to avoid execution.
"The Board has considered the totality of the information presented in this case and thoroughly deliberated on it, after which the decision was to deny clemency," the state body said in a statement.
Davis was convicted of the 1989 killing of police officer Mark MacPhail near a Burger King restaurant in Savannah, Georgia. MacPhail's family says Davis is guilty and should be executed.
He is due to die by lethal injection at 7 p.m. local time on Wednesday at Georgia Diagnostic and Classification Prison in Jackson, Georgia.
Nobel Peace Prize laureate Desmond Tutu and Helen Prejean, -- who wrote "Dead Man Walking," a book about a death row inmate -- have issued statements on Davis' behalf, and around 2,000 people including civil rights leaders rallied in his support on Friday.
A further rally was planned for Tuesday evening on the steps of the state capitol building.
In a measure of international concern about the case, the Secretary General of the Council of Europe, Thorbjorn Jagland, on Tuesday appealed in a statement to U.S. authorities to "find a way to spare the life of Troy Davis".
"The reason is not only our disagreement over capital punishment but first and foremost the serious doubts which persist about the integrity of the conviction," he said, adding that he did not want to be perceived as interfering.
'A CIVIL RIGHTS MATTER'
Raphael Warnock, pastor of Ebenezer Baptist Church in Atlanta, called the impending execution a "civil rights violation and a human rights violation".
"We are determined to fight on behalf of Mr Troy Davis and on behalf of justice in Georgia," Warnock told a news conference held at his church, which was once led by civil rights leader Martin Luther King.
He and other Davis supporters called on Savannah district attorney Larry Chisolm, a key figure in the case, to appeal for the death warrant to be vacated and said they also wanted the parole board to reconsider its decision.
But Davis' legal options appear slim, not least because Georgia's constitution gives authority on pardons and paroles to the board so no appeal to the governor is possible.
"It doesn't seem like there is a strong legal option at this point. This (the parole board hearing) is most likely it," said Anne Emanuel, a law professor at Georgia State University who advises Amnesty International USA.
The case has been through a series of appeals and the U.S. Supreme Court took the rare step in August 2009 of ordering a new hearing for Davis to assess what his lawyers said was new evidence showing his innocence.
The justices transferred the case to a U.S. District Court in Georgia for a hearing and determination of his claims that new witnesses will clearly establish his innocence. A year later, the judge, William Moore, rejected Davis' claims of innocence.