I don't get it.
A person is not allowed to avenge the death of his kin by striking revenge upon the murderer with his own hands...yet the government is permitted to do it with taxpayers' money, because it is somehow more just and humane to kill a murderer in that manner.
I say, when found guilty--leave the punishment decisions up to the victim's family. It is so much more fair that way to all taxpayers, victims--and even murderers.
Interesting point.
Lawyers make the laws and Lawyers make money litigating.
This looks like a conflict of interests.
Your idea is similar to Shia Islam law.