Why put somebody on death row then?

I just read about somebody who was on death row for 22 years. I would like to know why this guy was not…I don’t know…put to death. What the hell is wrong with this picture. They kept him on death row for 22 years and then they released him under house arrest. No need to explain the rights of a human being even if they are criminals. In my opinoin, if you do something to get put on death row you have no rights.