Why does looting happen in riots

This involves a psychological factor of the human mind. People loot places in the midst of pure chaos because they are in a such a state of excitement, anger, etc. To think in ways similar to a criminal, just put yourself in the situation. You are in the middle of a huge mass of people, all who are doing crazy, ridiculous, and illegal things. Cars are on fire, stalled or abandoned in the roads. Broken glass is everywhere. Any police or military personell are in a frantic state, doing everything possible to enforce law. Any law obeying, mild-mannered shopkeepers or what-have-you have fled the area. Whatever you want is your for the taking as long as you have the means to transport it somewhere to store. It's a crazy thing, but it happens.