I learned long, long ago that you will NEVER change some individuals' minds about any authority figure, especially police officers. My maternal grandfather, after whom I was named, wanted nothing more to do with me when I became an officer. He thought all police officers were crooks and I'm sure there was no way his mind could be changed. I just said I was going to join the police department and find out what kind of people they were.
Well, as most people know, but seem to forget sometimes, the only place we have from which to hire police officers is the human race, and they ain't all perfect. And there are certainly a lot of the wrong kind of people who want to be officers. I was my department's first recruiting officer as a patrolman and some years later I was commander of the personnel division and had the final say as to whom we hired and whom we rejected. I can remember a time when only 3% (yep, 3 out of 100) applicants were accepted. You probably wouldn't believe the reasons some of the applicants wanted to be officers.
However . . . ., we still got some bad ones at times, and we always will. When I started, I was in a recruit class of 29. One was later fired for a petty theft and one was sent to prison for burglary. I can think of a couple of others (not in that recruit class) who were sent to the state prison during my tenure. And I, personally, got resignations from a couple of bad officers, and did the necessary paperwork to fire some.
AND . . . . I can tell you for sure that some of the finest, most honest, individuals I've known were police officers, and as you would expect, some of the sorriest individuals I've known were police officers. IN MY OPINION, it pretty much boils down to the departments' management; the chief, assistant chiefs, captains, etc. If they insist on their officers following the rules, you'll have a good department, but if they were not good honest officers themselves; just good politicians, you'll have problems.