The most accurate and concise definition of evil I know is 'power without accountability.  Cops routinely and egregiously abuse their power because they know they won't be held accountable by doddering sheep always giving them 'the benefit of the doubt.'  Every cop holds the power of life and death over everyone around him.  That places cops near the top of the 'evil' list.  Not too far below them are those who refuse to hold them accountable for their crimes.