I have lots of respect for honest cops. I think they are great people and true heroes on many occasions. They do screw up though, especially with young cops. They make errors in judgment.
I have seen cops hit people when they didn't have to. I have seen SWAT teams (Navy Seals too for that matter) come into my bar and get drunk as hell and drive 40 miles to a casino or down the road to a strip club. I was at a strip club one night at 3:20 am (beer sales cut off at 3 by city ordinance) and got a beer from the bottle only poured into a mug. Being a bartender I know this is illegal. I turn around and there is a cop two feet in front of me. I edge around him and ask the waitress how they got away with it. Since I knew a few people that worked there and we were tipping fat, she may have been telling the truth when she said, "Oh don't worry we pay them off."
I went to that club maybe 25 times over about a 5 year span. Every instance I was there I saw massive law violations. Someone opens the door to the women's bathroom (or you get pulled in there by a stripper) and there about 3-4 people doing coke.
In the back room there would be on average about 12 couples breaking the law with contact. 2-3 would be in a back corner getting more intimate than a lap dance. This club was considered a top 50 club nationally at least and was all of a block from the precinct station. In a massive 3 year investigation, they uncovered evidence of drugs and prostitution and were finally able to close down the place.
I think it cost about 250k for the investigation, but worst cast scenario using OCin math it was at least 20k.