Condemned death row inmate Troy Davis is running out of time. Yesterday, just after 8 a.m., the 5 member Georgia Pardons and Parole board denied the 42-year-old’s petition for clemency.

It’s been 20 years since a jury convicted Davis of gunning down off-duty Savannah police officer Mark MacPhail who had rushed to help a homeless man being assaulted by Davis and an accomplice in 1989.

In all of those years it has never dawned on Davis or his attorneys to prove his innocence by taking a polygraph test — until yesterday.

According to the Atlanta Journal Constitution, Stephen Marsh, one of Davis’ lawyers said “Mr. Davis believes he is innocent and he wants to show it.”

But before he agrees to take the polygraph test, Davis wants some assurance from the parole board that it will take his test results into consideration, Marsh said.

“He’s not going to spend three hours away from his family on what could be the last day of his life if this does not make any difference,” said Marsh.

But wouldn’t it have made more sense for his attorneys to have gone before the parole board on Monday armed with a copy of a polygraph test that proved their client’s innocence?

Innocent men behave innocently. An innocent man would have turned himself in 22 years ago when he learned the police were looking for him in connection with the death of a police officer.

An innocent man would have demanded a polygraph test right away to prove he wasn’t the cop killer they were looking for.

It is doubtful that the Department of Corrections will approve Davis’ polygraph exam request at the 11th hour. Davis’ lawyers say they will show up at the state prison in Jackson with a polygraph examiner this morning anyway.