No, killing people who have killed people to punish them for killing people is what's worthless. It's a bloodthirsty and unproductive solution.
That's the problem with how our legal system is seen - "it is to punish."
It is not to punish. Nor should it ever be seen as a tool of punishment.
The legal system is a tool for society's survival. It is our immune system against individuals that seek to corrupt and destroy something that makes it easier for us to function efficiently and without constant suspicion of each other.
It should have two goals - to curb non-violent crime through the use of community service and/or fines, and to eliminate from our society those who only survive by violent extortion.
If there's a murder case and there is insufficient evidence to suggest the person is likely to kill again - leave them the hell alone. You're not going to 'make them pay' by throwing them in jail, taking away their job and 15 years of their life. If they are that bad - just kill them or exile them to human traffickers in China and South America.
The idea that you can somehow use the current system as 'punishment' turns the entire court system into a public arena akin to the Coliseum. Gladiators are thrown before the lawyers and jurors while the public looks on and cheers for the gladiator or the lions depending upon whether or not they believe the person needs to be punished.
There should be three sentencing options for our courts: Fines. Community Service. Death (or sell them off to the ***/slave trade if you want to be humane). Jails should only be used to detain those who are on trial for violent crimes with reasonable suspicion that it will be committed again. If someone 'escapes justice' in another country - let that country know what the story is, and let them decide if they want him/her living amongst them; He/she is no longer our problem.
Honestly - I've grown disgusted with our country's court system. If I do something, and you think it's bad enough to lock me away for ten years (after two years of playing with the circus court), then you may as well just kill me. If you don't have the balls to kill me over whatever I did - then I can't be scary enough to warrant locking me away; and you can assign me community service or a fine.
If I start going around and raping women and leaving their bodies to dangle over the overpass... you probably want to just kill me.
If I steal a car and run through someone's corn field - I should be fined for the damaged property with, perhaps, a little bit of community service. I should not be locked away in jail, lose my job, and then be picked up a few months after release for selling drugs (or whatever).
Our current system is completely dysfunctional and creates far more problems than it resolves.