The Last Mile by David Baldacci (2016) Grand Central Publishing

Melvin Mars was a Heisman finalist, his world was set, he was a shoo-in as a first round pick in the NFL draft.  Until his parents were killed and he was convicted of their murders.  He got the death penalty and now he’s going to walk the last mile.  Only it’s just a couple hundred feet.  When they come to get him, it’s not to go into the death chamber.  It’s because another prisoner on death row in another State has confessed to the murders of his parents.  Amos Decker has heard about it on the radio while driving to D.C. and wants to investigate what’s going on.  It’s definitely not what it seems.