‘They’re Cops; They’re Going to Beat You’ LewRockwell.com Blog (2010-03-25):

When the victim of a criminal assault dials 911 for help, what happens if police are the assailants? Chicago residents Matthew Clark (a Ph.D. lecturer at the University of Chicago) and Gregory Malandrucco (who is finishing his Ph.D.) can answer that question: The cops who respond to the call will...

You got served and protected. (Cont'd.) Keep in mind that when a gang of blue-bangers starts beating on you in a public place in front of God and everyone, you're still better off not calling 911: if you do, they'll only send reinforcements.