If the tests, which Warner is expected to order before he leaves office in mid-January, clear Roger Coleman, death penalty opponents say it would be the first time an executed convict is scientifically shown to be innocent.
"The final argument (of death penalty advocates) is that no innocent person has been executed," Richard Dieter, director of the Death Penalty Information Center, a Washington group that seeks to end capital punishment, told USA Today.
"If you find an innocent man who has been executed, that's a final nail through that," Dieter said.
Forensic Science Associates of Richmond, Calif., performed DNA analysis before Coleman's execution, using a now-obsolete technique that could not exclude Coleman or say definitely that he did it.
2014: The Year in Music [PHOTOS]