Violence begets violence.
Playing World of Warcraft: The Mists of Pandaria, one of the main themes of this expansion is the addressing of the horrific violence between the Horde and Alliance. Every action begets an equally strong reaction. One scene from one of the solo-player scenarios shows two leaders sniping at each other about who did what to whom for various reasons of past wrongs and both promising retribution against each other. The Pandarean leader, who is a neutral person in the conflict, silences both of them and fiercely tells them..."Only YOU can end the cycle of Violence by putting down your weapons and walking away." After they both hear his words, Lady Jaina Proudmoore, a human leader who's city was destroyed by the equivalent of a nuclear bomb, and Lor'Themar Theron, the leader of a race called "The Blood Elves", consider his words carefully and simmer down. In a moment of clarity and civility, the two leaders dismiss themselves and their contingents from the battlefield with a slight bow and respectful acknowledgment of each other and walk away from each other in a cordial manner.
Friends, it's time we do the same. Retribution against anyone will not restore who has been lost and fix who has been traumatized today. Nobody deserves death out of vengeance for this travesty. If the law sees fit to condemn someone to death after a court of law hears the evidence, then that is the law's right. But vengeance is not why we seek justice.