Defense attorneys asked the Georgia pardons board to grant clemency to Troy Davis who is scheduled to be executed for the 1989 slaying of an off-duty Savannah police officer.
Attorney Stephen Marsh said he told the Georgia Board of Pardons and Paroles on Monday that there was substantial doubt about Davis' guilt. He and others urged the panel to spare his life.
Davis is scheduled to die Wednesday for Mark MacPhail's murder. It is the fourth time in four years the state has tried to execute him, but now his legal appeals are exhausted.
Prosecutors say there's no doubt Davis murdered MacPhail, and courts have repeatedly upheld his conviction. Prosecutors will present their case later.
Davis' supporters rallied outside the office, waving signs that said "Free Troy Davis."