I spent a lot of time in what's currently CHAZ/CHOP as a teen. The police in that precinct have/had a particularly visible habit of blowing red lights. When there are other cars nearby, they flick their lights on momentarily, as if ticking off a minor technicality (though still violating the letter of the law). I've seen cops do that pretty much anywhere I've lived, US or Canada, but it was especially prevalent on the stretch of road a few blocks from the precinct. I saw quite a few near-misses caused by this.
An "honest" cop would see this behavior and report the crime appropriately. But they simply don't hold eachother accountable.