In 1887, William Marion was hanged for murdering his friend John Cameron in Nebraska. Here’s what happened: a body identified as John Cameron was found in 1873. Marion was suspected of the murder, because he had been seen traveling with Cameron’s horses earlier that year. Marion was tried, convicted, and eventually hanged in 1887.
But four years later, Cameron reappeared! Turns out he had fled to Mexico, to avoid a paternity claim, and before leaving had sold his horses to Marion. He had not heard about Marion’s arrest and conviction until after Marion had been executed. In March 1987, 100 years after William Jackson Marion’s hanging, Nebraska Governor Robert Kerry pardoned him.