A novel idea for dealing with violent crime

[T. A. Gardner]

These are nations that have the death penalty. https://worldpopulationreview.com/country-rankings/countries-with-death-penalty They are not enlightened or sophisticated nations. They are low types with often strong religious control.

How "enlightened" is it to stick someone in prison where they then kill someone while in prison? Did the person killed in prison by another prisoner deserve to die? What kind of punishment will you give the killer?