A blogpost at rickfalkvinge.se recently talked about a few of those cases (site down for the moment). In particular, I was referring to the Ian Tomlinson case, but there have been similar events in Sweden and elsewhere.

I have yet to hear a police brutality case where an coverup was fully prosecuted to the point where all police officer involved (and who did nothing) was sentenced. It just do not happen. By the time it gets out, it has become personal and political.