In cases like these, things like media bias are very real. Absolutely there are cops that show brutality on camera, and some off camera, but there were around 705,000 sworn in police officers in the united states in 2010, and statistics show that only a tiny tiny fraction of them engage in misconduct.
In 2010, there were 4,861 unique reports of misconduct, with 6,613 sworn in officers involved in the incidents. Lets give a little more just to account for undoubtedly undocumented cases, so the total is now 9,000 involved. This means that only .009% had documented misconduct against them, and an estimated .012% in total.
Should we just generalize that most officers are brutal, and that our police force is corrupt, when 99.988% of officers are estimated completely innocent? Even with my probably wide margin of error, that is still a very honorable statistic.
America likes to latch on to media bias. In the summer of 2001, everyone was getting up in arms about the dangers of sharks. Vacations to beachy areas were canceled, and even time magazine had a shark featured on their front page. Despite all this hooplah about sharks, shark attacks had actually been down from 11 casualties to 4 that very year. While everyone was declaring a war on sharks sharks were munching on other foods instead.
So while police brutality is a terrible thing, it's been blown out of proportion by the media and internet wanting something to latch onto, and skewing statistics in our minds that the police are out of control and not our friends. This has negatively impacted the police's ability to regulate crime, because they don't want to appear racist and lose their jobs, and or reputation. So do we give them the benefit of the doubt? Generally, yes, but not to dismiss the case either. If the percent of perfectly capable and honest officers is that high, assuming that they're part of that 99.988% isn't a long shot, though they shouldn't ignore the .012% chance.