As we've discussed here before, Rick Perry is pretty damned insistent that he did not kill an innocent man. For a millisecond, it seemed like he might be right, because Cameron Todd Willingham's ex-wife said he confessed to her.
But she's a liar. Other places won't say it, but I will. She lies. She's a lying liar who lies. Maybe he did confess, but it contradicts everything else she's ever said. So she lied then, or she's lying now. But by any definition, she's a lying liar who lies.
Grits for Breakfast has an excellent breakdown of her inconsistencies, but let's just take one - her statement to the Corsicana Daily Sun in 2004. In that story, she said she became convinced of his guilt, but that even a pre-execution visit didn't result in a confession to her.
She either lied then, or she's lying now.