ATLANTA (Reuters) - A condemned man set to be executed by lethal injection on Wednesday for killing a Georgia police officer in a high-profile case wants a polygraph test in a last-ditch bid to show his innocence, Amnesty International USA said.
Troy Davis' case has attracted international attention and an online protest that has accumulated nearly one million signatures because of doubts expressed in some quarters over whether he killed police officer Mark MacPhail in 1989.
Davis' best hope of avoiding execution, set for 7 p.m. local time on Wednesday, lay with the Georgia Board of Pardons and Paroles but on Tuesday it denied him clemency following a one-day hearing.
"Troy is so insistent of his innocence that he is willing to take a polygraph. I think it's a bit of a risky strategy. Polygraph tests are not the most solid type of evidence," said Laura Moye, a spokeswoman for Amnesty.
The legal procedure for getting permission for a polygraph test would likely involve the district attorney of Chatham County, where the crime was committed, or the state paroles board, she said.
"There are a number of legal filings at a number of different courts that they (his lawyers) are trying to see what they might be able to do to try and stop this execution," Moye said.
Davis was convicted of murdering police officer Mark MacPhail outside a Burger King restaurant, shooting him twice as he went to rescue a homeless man who was being beaten. MacPhail's family say Davis is guilty and should be executed.
Since his conviction, seven of nine witnesses have changed or recanted their testimony, some have said they were coerced by police to testify against Davis and some say another man committed the crime.
No physical evidence linked Davis to the crime.
Amnesty and the National Association for the Advancement of Colored People plan a protest outside Georgia's Diagnostic and Classification Prison later on Wednesday.
(Writing by Matthew Bigg; Editing by Jerry Norton)