The Georgia Board of Pardons and Paroles Tuesday denied a clemency appeal from Troy Davis, who is scheduled to die Wednesday.

Davis' lawyer Tuesday said that he has asked prison officials and the pardons board to let Davis take a polygraph test before his scheduled execution.

The Georgia death row inmate’s lawyer Stephen Marsh told The Associated Press that he hopes the pardons board will agree to consider results of the test.

Davis is scheduled to die at Georgia Diagnostic and Classification Prison near Jackson by a lethal injection on Wednesday night after parole board denied last-minute plea for clemency on Tuesday morning.

The machines aren't reliable enough to convict anyone, but they may tell you something about innocence, Marsh said.

Marsh said that Department of Corrections has yet not cleared Davis' legal team to administer the test Wednesday, but Davis' lawyers will be present at the state prison with a polygraph examiner in the morning, he said.

He also wants some reassurance from the parole board that it will take his test into consideration, Marsh said.

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

The 42-year-old is convicted of killing off-duty Savannah police officer Mark MacPhail in 1989, but his family, lawyer and many supporters believe that he is innocent. His execution has gained international attention since no physical evidence was presented against him during trial. Multiple witnesses have recanted or changed their stories in the years after the murder.

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

But the slain officer's family believes 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.