How an overzealous forensic pathologist and his odontologist sidekick put innocent Mississippi residents behind bars – and let killers run free.

On the country’s poorest.

"I remember lying on my side, dust everywhere, and I looked down and saw my arms were split open and squirting blood and I had just two bloody stumps above my knees," said Marine 1st Lt. James Byler, 26, who was blown up a few weeks before Mark Litynski. "My first coherent words to my Marines were, 'Hey! check my nuts!'

Three primary reasons: A desire for vengeance, the sanitization of executions and, ironically, the reliability of DNA evidence.