Does police aggression cause crowd violence?

That's very much the kind of process that we focus in on. We call it a self-fulfilling prophecy; it's the expectation that a large crowd of supporters is going to cause a problem and then what you do is throw resources at it because you feel you need to control it. The idea is very traditional that the crowd is very irrational and it needs to be controlled. Resources are thrown at it and the expectation of trouble means that the officers are stressed and wearing protective equipment. They're much more likely to lash out and then if a small incident occurs in that crowd, then what we see is what people call a heavy handed reaction, which is basically a large number of officers driving forcefully into the crowd. That crowd contains people that haven't done anything wrong and didn't intend to be involved in violence. They find themselves being physically assaulted and it makes them wonder why they are being treated in that way. This draws people in the crowd into violence when they had no intention prior to police intervention of engaging in violence.