http://www.ojp.usdoj.gov/bjs/dtdata.htm#crime
If you do not find what you want, try to contact them directly, they are very helpful and should be able to direct you to the right data set, if it exists.
However, the problem that you are facing is that it is unlikely that any data source will have a category "folk were arrested, questioned, beaten etc or protesting, or speaking out against." This is a value judgment, and you need to ferret it out from the information about the disposition of the case e.g. whether it was prosecuted.
Wojtek
-------------- next part -------------- An HTML attachment was scrubbed... URL: <../attachments/20061220/178dc245/attachment.htm>