DC's critical mass has been experiencing the same form of police harassment and brutality for a while now, not every ride, but enough to make us weary of it and hesitant to ride.
I suggest someone get a bunch of throwaway cameras and distribute them throughout the riders. When the police begin to misbehave, if they don't have badges or name tags on, just capture it all on film. It won't be hard to establish a pattern and practice of police abuse. If the police are aware that a legal suit is being prepared, they may learn fast how to behave more like professionals and less like thugs and hoodlums.

I made this same suggestion on our CM list over the weekend, and there were no police on our ride yesterday. Think there's some connection? Maybe not, but maybe. Especially since 3 class action lawsuits were recently filed in DC based on police misbehavior.