As I mentioned a few minutes ago, in some of the human rights organizations that have tried to document it, there is some record of police—what can I say—overaction, perhaps, such as not handling situations well and detaining people. People are detained for short periods of time and then released after a protest—even journalists, etc. Many of these detentions are short term, and then nothing happens.
There might be some contribution, but I don't have evidence that police brutality is a major problem, if that's your question.