““Will no one rid me of this meddlesome priest?” asked Henry II as he instigated the murder of the Archbishop of Canterbury, Thomas Becket, in 1170. Down through the ages, presidents and princes around the world have been murderers and accessories to murder, as the great Harvard sociologist Pitirim Sorokin and Walter Lunden documented in statistical detail in their masterwork Power and Morality. One of their main findings was that the behavior of ruling groups tends to be more criminal and amoral than that of the people over whom they rule.”

asked Henry II as he instigated the murder of the Archbishop of Canterbury, Thomas Becket, in 1170. Down through the ages, presidents and princes around the world have been murderers and accessories to murder, as the great Harvard sociologist Pitirim Sorokin and Walter Lunden documented in statistical detail in their masterwork Power and Morality. One of their main findings was that the behavior of ruling groups tends to be more criminal and amoral than that of the people over whom they rule.
Killer Politicians, Project Syndicate - The World's Opinion Page, Oct 24, 2018 https://www.project-syndicate.org/commentary/killer-politicians-include-american-presidents-by-jeffrey-d-sachs-2018-10

1960s, Where Do We Go from Here: Chaos or Community? (1967)
Context: I say to you today that I still stand by nonviolence. And I am still convinced that it is the most potent weapon available to the Negro in his struggle for justice in this country. And the other thing is that I am concerned about a better world. I'm concerned about justice. I'm concerned about brotherhood. I'm concerned about truth. And when one is concerned about these, he can never advocate violence. For through violence you may murder a murderer but you can't murder murder. Through violence you may murder a liar but you can't establish truth. Through violence you may murder a hater, but you can't murder hate. Darkness cannot put out darkness. Only light can do that.

Source: The Broken God (1992), p. 278

Source: Death: A Poetical Essay (1759), Line 154. Compare: "One to destroy is murder by the law, And gibbets keep the lifted hand in awe; To murder thousands takes a specious name, War’s glorious art, and gives immortal fame", Edward Young, "Love of Fame", Satire vii, line 55.

Source: On Crimes and Punishments (1764), Chapter XXVIII

Cain, Saga of the Swamp Thing #33
Swamp Thing (1983–1987)

Source: La coscienza di Zeno (1923), P. 28; p. 34.

Bk. 1, ch. 7, sct. 1
The Ministry of Fear (1943)

Ch 26
A Canticle for Leibowitz (1959), Fiat Voluntas Tua
Context: The abbot snapped off the set. "Where’s the truth”? he asked quietly. “What’s to be believed? Or does it matter at all? When mass murder’s been answered with mass murder, rape with rape, hate with hate, there’s no longer much meaning in asking whose ax is the bloodier. Evil, on evil, piled on evil. Was there any justification in our ‘police action’ in space? How can we know? Certainly there was no justification for what they did — or was there? We only know what that thing says, and that thing is a captive. The Asian radio has to say what will least displease its government; ours has to say what will least displease our fine patriotic opinionated rabble, which is what, coincidentally, the government wants it to say anyhow, so where’s the difference?"