Here is an interesting paper on that very subject:
http://www.constitution.org/lrev/roots/cops.htm
I am sympathetic to this view, but I think of course it would need to be updated due to the march of technology, the need to have people with at least a modicum of training in forensics go over crime scenes and access to labs, etc.
However, I genuinely believe these to be
solvable problems. I don't have any such confidence in these problems (which seem to be a regular occurance in departments across the nation, not just DPD) that give rise to bad cops acting inappropriately can be solved without a huge overhaul of the entire system police operate under. What bothers so much isn't that the particular police officers acted inappropriately, but the tremendous amount of leeway and benefit of the doubt they get. I think good, honest cops get a minimum benefit from all this, but bad cops get a ton of benefit.
The system bothers me a tremendous amount more than the existence of bad cops.
I think the entire concept of police stems from collectivist premises, as well - the idea that there is a special class of people endowed by whatever power, God, Genes or whatever you wish, as superior beings who do not need to play by the same rules. These are our enlightened rulers, who know better than us how to run our own lives, or the police, who are better equipped to judge when the use of force is appropriate and so need not be held to the same standards as typical citizens.
Keeping the peace and fighting crime is properly a function of the entire community, not a special elite held separate and above citizens at large. I don't care to accuse any particular cop or police in general as corrupt; but I do think the system they operate under is.
A good first step, I think, would be to simultaneously overhaul the legal system to make frivolous lawsuits harder on the claimant vs the defendant (ie loser pays,) to protect cops from people suing them only to bankrupt them (hell, to protect everyone from that,) and to make police officers personally responsible for any misconduct vs being granted immunity as members of a special class of people.