As much as I am suspicious at the "evidence" available during a messy and chaotic riot ("protest") I have seen too many false assault claims all over the world that I give the chinese LEO the benefit of the doubt. Not to mention, who would try to assault a girl when more pressing matters are at hand in those situations?
Those who cry wolf with rape/assault only make it harder for those who are actually violated to be trusted. In most cases it is just he said, she said.
