Regarding the motive to bring it to bring the perverse incentive to light, it is possible that an institutional cover-up exists nationwide, but highly unlikely given the Christian Ethos that existed in this country...
If that is the case, and a perverse incentive exists for cops to arrest the innocent, then we should see this occurring all over the country and across all racial groups
Non sequitur - we'd see it only if it were commonly the case that someone who knew of it had motive to bring it to light.