One of the problems with modern police politics is that there is basically no way for occupied populations to actually purge their corrupt police.

Time was, theoretically, you could at least mobilize to throw the bastards out (see the Battle of Athens) within reason and let the community heal itself.

Nowadays, though, the militarization of police and the desire of the .gov to crackdown on that sort of thing helps create this sorts of festering pockets of corruption that cannot be replaced because to do so is highly illegal.

(On a related note, this is part of the reason a great many people are reluctant to disarm or to accept legislation that would put them further at the mercy of police.)