During the 2010 G20 Summit in Toronto Canada, the police claimed that they were working to stop attacks by the Black Bloc Anarchist group.
In doing so, the Police became the Blue bloc for illegally detaining over 200 citizens against there will while not under arrest.
The police in Riot gear would step forward, (identity hidden by helmets) target an individual with their clubs and shields. Then step back into formation thus making it very difficult to identify the specific office who assaulted the citizen.
Just like the black-bloc
Dude, Heads up, the blue bloc is locking up more protesters.