Cops often let off hook for civil rights complaints
triblive.com
triblive.com
Of those 4% who do get investigated, about 3 out of 4 don't get indicted, because the prosecutor delivers the case in such a way that the Grand Jury forgives them, even though in 99% of the non-cop related cases, the prosecutors manage to score an indictment.
So basically only 1% of cops ever get punished for their crimes.