Troy Davis seeks polygraph as execution looms

(CBS/WGCL/AP) ATLANTA - Condemned Georgia inmate Troy Davis is set to be executed Wednesday after he lost what had been his most realistic chance at avoiding lethal injection, but his supporters haven't stopped fighting to save his life, requesting a polygraph test and urging prison workers to strike.

Davis was left with little to do Tuesday but wait to be executed for a murder he insists he did not commit after Georgia's pardons board rejected his appeal for clemency.

As his scheduled 7 p.m. Wednesday execution neared, his backers resorted to far-fetched measures. They asked prisons officials to let him take a polygraph test; urged prison workers to strike or call in sick; asked prosecutors to block the execution and they even considered a desperate appeal for White House intervention.

CBS News legal analyst Andrew Cohen described the denial of clemency as "routine."

"Parole boards almost never grant clemency, so this is not a surprise," Cohen said. "Now if Wednesday's execution is going to be halted it's going to have to come from the federal courts, and the U.S. Supreme Court in particular, which last week halted a Texas execution."

Davis has gotten support from hundreds of thousands of people, including a former FBI director, former President Jimmy Carter and Pope Benedict XVI, and a U.S. Supreme Court ruling gave him an unusual opportunity to prove his innocence last year. State and federal courts, however, repeatedly upheld his conviction for the 1989 killing of Mark MacPhail, an off-duty police officer who was working as a security guard in Savannah when he was shot dead rushing to help a homeless man who was being attacked.

According to CBS affiliate WGCL, Davis' attorneys say he was convicted based on flawed testimony that has been largely recanted by witnesses, but prosecutors and MacPhail's relatives say they have no doubt the right man is being punished.

"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."

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