I, Walrus, am in need of some advice.

My friend was robbed by 2 police officers and put through a huge ordeal. It only ended when the chief of police stepped in and gave him his money back, stating that they police officers were wrong and that they would be punished. Yet my friend still sees these police officers driving around doing whatever they want; in fact, not only is he unsure that they were actually punished, but he overheard the officers insisting that what they did to my friend was "fair" and "just".

How should I respond to this? What should I tell my friend to make him feel better? How can I tell him to trust the police when even I am unsure whether they can adequately protect us?

-WW
EDIT: THIS IS FOR CODY - http://i.imgur.com/j75vIc8.png