This is why getting rid of police unions will not solve the problem. Their most powerful tool is not collective bargaining, but political action committees (PACs). What I advocate is taking away disciplinary power from local control, and establishing state-wide, independent licensing and discipline agencies.

https://qcp.medium.com/dont-hold-your-breath-for-real-police-reform-6cd8514b592c

Of course, the police PACs will use all their power to oppose this. The more they fight, the more you know you are closer to your target.

I also recommend this book on how organizing against police violence has shaped social movements:

Edward J. Escobar, Race, Police and the Making of a Political Identity: Mexican Americans and the Los Angeles Police Department 1900-1945 (UC Press 1999).

https://www.ucpress.edu/book/9780520213357/race-police-and-the-making-of-a-political-identity