Ethan Bueno de Mesquita studied deterrence in a world where attacks cannot be perfectly attributed to attackers. In his model, each of n attackers may attack the defender. The defender observes an imperfect signal that probabilistically attributes the attack. The defender may retaliate against one or more attackers, and wants to retaliate against the guilty attacker only. He uncover an endogenous strategic complementarity among the attackers: if one attacker becomes more aggressive, that attacker becomes more “suspect” and the other attackers become less suspect, which leads the other attackers to become more aggressive as well.