It is not murder which is forgiven but the killer, his person as it appears in circumstances and intentions. The trouble with the Nazi criminals was precisely that they renounced voluntarily all personal qualities, as if nobody were left to be either punished or forgiven. They protested time and again that they had never done anything out of their own initiative, that they had no intentions whatsoever, good or bad, and that they only obeyed orders.
To put it another way: the greatest evil perpetrated is the evil committed by nobodies, that is, by human beings who refuse to be persons.

Hannah Arendt (1906-1975) German-American philosopher, political theorist

Lecture (1965-1966), “Some Questions of Moral Philosophy,” New School for Social Research, New York City
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This is from a series of lectures Arendt gave at the New School for Social Research in NYC (1965), and at the University of Chicago ("Basic Moral Propositions," 1966). These were reworked and collected under this title in Responsibility and Judgment, Part 1 "Responsibility" (2003).