Pub. L. 103–322, title XXI, §210402, Sept. 13, 1994, 108 Stat. 2071 requires the Department of Justice to compile an annual report on police brutality. This has not been done since 2001.
There is nothing that would stop this law from also reporting on misconduct that falls short of "brutality". In light of recent police activity this issue is getting attention and there is a neglected law that can shed light on the extent of the problem.
Appoint a leader such as Joseph McNamara to head up an DoJ task force to collect this data. While there are personnel and privacy issues with making the raw data publicly accessible every effort should be made to make mildly redacted data available for public research.