you refer to police officers?  As one with family members of multiple generations who are/were members of the NYPD, I can tell you how it really is.

 
Police in every city in the United States are a cross-section of the societies they serve.  There are good and bad people in our police departments.  Fortunately, way more good than bad.  They are human beings who have a very difficult job and often have to make split second decisions while under duress.  Obviously, occasionally human beings make mistakes.  Cops make mistakes.  Sometimes honest, forgivable mistakes.

 
Having said that, fortunately while they are in the minority, bad cops definitely do bad things, they do those bad things with malice and bad intentions.  These bad cops absolutely deserve to be weeded out   Because of the nature of police work and a culture that demands all cops have each other's back, it becomes increasingly difficult to weed these bad apples out.

 
This is why any good cop will always have his/her body cam on.  And if put in a situation where ALL the evidence is available, should never shy away from being second guessed in ANY operation they engage in.  True it takes time out of a cop's day and results in added paperwork, but it also adds to the integrity of the system