One character in The Plague, Jean Tarrou, has strong opinions on the death penalty, calling it murder and is so troubled by the concept that he actively rallies against it. He considers lawyers to be inhuman and judges straight-up "enemies." This may be a reflection of Camus’s humanist beliefs. If man is more good than evil, and if it is our job, as The Plague argues it is, to take up arms on behalf of man against pestilence, suffering, and death, what is the death penalty but a very act of treason against our own kind?
Criminality in The Plague is a case of societal roles; those labeled as criminals rise to the occasion and fulfill the expectations projected upon them.
Tarrou’s claim that we are all murderers, and that we must try to be "innocent murderers," is the perspective of a moral absolutist. He stands alone against the moral relativist world of The Plague.