Okay, I think I see what you're referencing. There really was a Black Jack Ketchum...He was hung and decapitated. He was convicted of felonious assault. The only person ever hung for the offence, which was later found to be unconstitutional. His actual name was Tom, so the Jack Ketchum is a bit confusing. He was also hung for assault...the penalty for that is up to four years in prison. Somehow they hung him for it.