This webpage contains several interesting reports on types of police oversight.
There are 2 articles that are overviews of police oversight and then several publications that review oversight at individual police departments.
Recent Reports – National Association for Civilian Oversight of Law Enforcement
— Read on www.nacole.org/recent_reports
Policing Practices and Law Enforcement Accountability | Cato Institute
— Read on www.cato.org/testimony/policing-practices-law-enforcement-accountability
This is the home page for the Chicago PD Civilian Office of Police Accountability (COPA). The website has data and reports on CPD.
— Read on www.chicagocopa.org/