An attorney for Georgia death row inmate Troy Davis said Tuesday he has asked prison officials and the pardons board to let Davis take a polygraph test before his scheduled execution.

Stephen Marsh told The Associated Press he hopes the pardons board will agree to consider results of the test.

The machines aren't reliable measures of guilt but they may tell you something about innocence, the lawyer said.

A prisons spokeswoman has said she was unaware of the request. The Georgia Board of Pardons and Paroles also didn't immediately respond.

The board denied Davis clemency Tuesday, leaving him facing execution at 7 p.m. Wednesday for a crime he has always insisted he never committed.

Davis' supporters have also asked prison officials to let him to take the polygraph. They have also urged prison workers to strike or call in sick Wednesday, asked prosecutors to block the execution and even considered an appeal for White House intervention, according to The AP.

Davis, 42, is set to die by lethal injection after being convicted of killing off-duty Savannah police officer Mark MacPhail in 1989.

Protest rallies have been held worldwide, and Amnesty International and the NAACP have asked the board to reconsider.

But the slain officer's family believe they are closer to peace now that Davis is scheduled to die.

Justice was finally served for my father, said Mark MacPhail Jr., who was an infant when his father was gunned down. The truth was finally heard.