It's rare to see a governor pardoning or granting clemency to a person who's been convicted of a horrible murder. Governors have the same political considerations as prosecutors, maybe even more so. Families, lawyers, and maybe some media care about wrongful convictions. But prosecutors and governors don't want to project concern about criminals. Some prosecutors would agree with me, and some would not.
Some prosecutors are so righteous, and so convinced of the defendant's guilt.
But I think a lot of people would agree with me. I was a prosecutor for ten years. I think I know something of the mind-set here. For the American prosecutor, the system is war. They see it as a total abstraction.