During the Obama Administration (2009-2017): The DOJ launched at least 25 pattern-or-practice investigations into police departments.
During the Trump Administration (2017-2021): The DOJ significantly reduced the number of such investigations and consent decrees. Only a handful of investigations were opened or continued during this time.
Biden Administration (2021-present):
From 2009 through the present, the DOJ has investigated approximately 30-35 police departments. This includes some that were investigated during the Obama years and others under subsequent administrations.
While honest, professional police officers are invaluable, strict accountability and transparency in policing are essential. Those entrusted with the power to arrest, detain, and charge people with serious crimes.
For the record, the Department of Justice recently found civil rights violations by the Phoenix Police Department and the city of Phoenix:
https://www.justice.gov/crt/conduct-law-enforcement-agencies
https://www.justice.gov/opa/pr/justice-department-finds-civil-rights-violations-phoenix-police-department-and-city-phoenix