Answer:
The verse states, the worth of humans life, no one is allowed to murder or kill an innocent human. If someone does, he kills the entire humanity. And the one who saves a single life, he saves entire humanity.
Only those people are allowed to punish, who kills someone who is innocent or damages the State like terrorism or any other activity which is not forgivable. But this is also done in restrictions. Only judiciary or State can do this action against the culprits according to the laws.