I have had this precise conversation with my wife, who used to be pro death penalty, coming from a country where it's still in force. If someone murdered her or my kids I'd want revenge for sure. I'd probably want to kill them myself, but if I did so I'd expect to be punished for it myself. I am still absolutely against the death penalty; it is not the state's place to take revenge on behalf of victims of crime. Whole life sentences are fine by me, but the death penalty is barbaric.
And not a statistic in sight.