Case of the missing pants

Should a man be executed when the state says it lost key evidence he insists would support his case?

That’s the situation in Kentucky vs. Brian Keith Moore, convicted of the 1979 murder of Virgil Harris in Louisville. Witnesses described dirt covered clothing the suspect wore.
At the time of the trial there was no such thing as DNA testing, but now there is, and Moore says he never wore the clothes in question.

Jefferson Circuit Judge James Shake ordered the garments tested with today’s technology, but police have been searching through evidence boxes for two months and can’t find the shoes and pants.

Moore claims another suspect, who has since died, set him up to get a deal for himself.
There was other evidence against Moore, but it was dirt on the pants and shoes that were used to place him at the scene of the murder. He insists new tests would cast doubt on whether he ever wore the clothes.

Should he be executed if there is a chance the missing evidence would have cleared him?
He’s been in jail almost three decades. I’d be willing to leave him there.