NEW YORK (CBSNewYork/AP) -- Groups of New Yorkers are coming together to show their support for a Georgia death row inmate set to die by lethal injection at 7 p.m. Wednesday.
Supporters of Troy Davis have planned vigils around the country and around the world ahead of his scheduled evening execution.
Davis was convicted of the 1989 killing of Savannah, Georgia police officer Mark MacPhail.
On August 19, 1989, MacPhail was working security at a bus station and rushed to the aid of Larry Young, a homeless man who prosecutors say Davis was bashing with a handgun after asking him for a beer.
When MacPhail got there, they say Davis had a smirk on his face as he shot the officer to death in a Burger King parking lot. Others have claimed the man with Davis that night has told people he actually shot the officer.
No gun was ever found, but shell casings were linked, prosecutors say, to an earlier shooting for which Davis was convicted. Witnesses placed Davis at the crime scene and identified him as the shooter. However, no other physical evidence was found, including blood or DNA, that tied Davis to the crime.
But since Davis' conviction in 1991, several witnesses have recanted their testimony and some jurors have said they've changed their minds about his guilt.
Still, prosecutors and MacPhail's family have staunchly backed the verdict and state and federal courts have repeatedly upheld his conviction.
Davis has received multiple stays of execution over the years and his case has even gone to the U.S. Supreme Court.
As his execution looms, there are at least two vigils planned in New York City calling for clemency in the case.
In Brooklyn, the group Progressive New Yorkers for Troy Davis is holding a rally and vigil at 6 p.m. on Atlantic Avenue between Nevins and Bond streets in Brooklyn.
The group says there will be several speakers at the event.
"It is unconscionable that the Georgia Board of Pardons and Paroles has denied relief to Troy Davis. Allowing a man to be sent to death under an enormous cloud of doubt about his guilt is an outrageous affront to justice," Larry Cox, executive director of AIUSA said in a statement. "Should Troy Davis be executed, Georgia may well have executed an innocent man and in so doing discredited the justice system."
As time ticks toward the execution, Davis has turned down an offer for a special last meal and planned to spend his final hours meeting with friends, family and supporters.
Meanwhile, two attempts to prove his innocence were rejected: a polygraph test and another hearing before the pardons board.
His attorney Stephen Marsh said Davis would only submit to a polygraph test if pardons officials would take it 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.
His lawyers, meanwhile, are trying the legal avenues left to them, filing a motion in a county court challenging the ballistics evidence and eyewitness testimony. A judge could at least delay the execution, which has happened three times before.
As for the new and changed accounts by some witnesses, an unmoved federal judge dismissed them during a hearing set up by the U.S. Supreme Court in 2010. He said while the "new evidence casts some additional, minimal doubt on his conviction, it is largely smoke and mirrors.''
It was the first time in 50 years that justices had considered a request to grant a new trial for a death row inmate. It set a tough standard for Davis to exonerate himself, ruling his attorneys must "clearly establish'' Davis' innocence, a higher bar to meet than prosecutors having to prove guilt.
Prosecutors say they have no doubt they charged the right person, and MacPhail's family lobbied the pardons board Monday to reject Davis' clemency appeal. The board refused to stop the execution a day later.
"He has had ample time to prove his innocence,'' said MacPhail's widow, Joan MacPhail-Harris. "And he is not innocent.''
Davis' supporters include former President Jimmy Carter, Pope Benedict XVI and a former FBI director, the NAACP, as well as conservative figures.
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