Should the killer (Jack Ruby) of a murderer (Lee Harvey Oswald) be imprisoned?

If one kills a murderer, he could be punished, but seriously not taken to prison?

Was it right for George Milton to kill Lennie Small, after killing beloved Curly’s wife, mice, and a dog?

If it’s all right to kill Lennie, then I reckon it’s (almost) all right to kill the assassin of John Fitzgerald Kennedy. Get me wrong not — I agree that two wrongs make no right.

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The Princess Bride is also a good example: Count Rugen killed Domingo Montoya, so his son, Íñigo, killed Rugen for vengeance, but no-one seems to want Íñigo to be killed.
Should the killer (Jack Ruby) of a murderer (Lee Harvey Oswald) be imprisoned?
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