Url https://policing.umhistorylabs.lsa.umich.edu/s/detroitunderfire/item/5615 Title Political Surveillance Map from Cockrel Files Source Box 2, Kenneth V. and Sheila M. Cockrel Collection, Walter P. Reuther Library, Archives of Labor and Urban Affairs, Wayne State University. Interactive version: https://arcg.is/ObXr0 --