Fact Sheet

The Facts on Pattern-or-Practice Investigations

How the U.S. Department of Justice Can Bring About Police Reform and Accountability

The U.S. Department of Justice seems poised to restore pattern-or-practice investigations to promote constitutional and effective policing.

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 (Getty/Andrew Harnick-Pool)
U.S. Attorney General Merrick Garland leaves after speaking about a jury's verdict in the case against former Minneapolis police officer Derek Chauvin in the death of George Floyd at the U.S. Department of Justice in Washington. Garland announced a civil investigation into Minneapolis policing practices in April 2021. (Getty/Andrew Harnick-Pool)

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On April 21, 2021, one day after a Minneapolis jury convicted former police officer Derek Chauvin for the murder of George Floyd, U.S. Attorney General Merrick Garland announced that the U.S. Department of Justice (DOJ) had opened an investigation into the city of Minneapolis and the Minneapolis Police Department (MPD). The civil probe will assess whether the MPD engages in a pattern or practice of unconstitutional or unlawful policing, marking the first pattern-or-practice investigation under the Biden administration. Less than a week later, Garland announced a second investigation, this time into the Louisville/Jefferson County metro government and the Louisville Metro Police Department, whose police officers shot and killed Breonna Taylor in her apartment while executing a no-knock search warrant.

As the DOJ under the Biden administration ramps up its use of pattern-or-practice investigations, here is what you need to know about this vital tool for bringing about police reform and accountability.

What are pattern-or-practice investigations?

In 1994, in the aftermath of an independent commission’s finding that linked the beating of Rodney King to institutional failure within the Los Angeles Police Department, Congress authorized the attorney general to investigate law enforcement agencies for “a pattern or practice of conduct…that deprives persons of rights, privileges, or immunities secured or protected by the Constitution or laws of the United States.” These investigations, commonly referred to as pattern-or-practice investigations, focus on widespread or systemic misconduct—as opposed to isolated or sporadic instances of wrongdoing—which might include routine uses of excessive force; repeated stops, searches, or arrests that are unreasonable; and discrimination based on race, ethnicity, national origin, religion, disability, or sex. As such, pattern-or-practice investigations differ from criminal civil rights prosecutions of individual law enforcement officers by the DOJ, which focus on specific instances of police misconduct.

How do pattern-or-practice investigations work?

The Civil Rights Division of the DOJ first identifies potential subjects for investigation by examining publicly available information, allegations brought by witnesses and complainants, and its own research on common or developing issues in law enforcement nationwide. If the division decides to open a probe, the Special Litigation Section immediately engages a variety of stakeholders in the jurisdiction, including community members and victims of police misconduct, officers at all levels of rank, police unions and affinity groups, and local government leaders. And while no investigation is the same, almost all involve reviewing written policies and systems for accountability, observing officer training and activities, and analyzing data of relevant incidents.


Percentage decrease in serious use-of-force incidents in Seattle eight years after it went through a pattern-or-practice investigation that resulted in a consent decree.

Office of the Mayor of Seattle, "City of Seattle Releases New Reports Showing That Seattle Police Department Sustained A Dramatic Reduction in Serious Use of Force and Continues Significant Reforms Under Federal Consent Decree" (2019).

At the end of the probe, the division issues its findings in a public report or letter. If the law enforcement agency is found to have engaged in a pattern of unconstitutional or unlawful policing, the division can negotiate a reform package with the police department to remedy the systemic failures identified during the investigation. A federal court signs off on the legally binding agreement, called a consent decree, and often appoints an independent monitoring team to oversee the implementation of the mandated reforms. Alternatively, the DOJ can offer reform recommendations that are not legally binding in a technical assistance letter or negotiate a memorandum of agreement—a court-enforceable contract that is similar to a consent decree but does not require ongoing oversight. If an agreement cannot be reached, the division may look to compel the reforms through civil litigation.

How have states used pattern-or-practice investigations?

Building on this federal model, a number of states have statutorily empowered their state attorneys general to conduct their own pattern-or-practice investigations. In 2000, California became the first to do so, prompting then-state Attorney General Bill Lockyer to secure a consent decree with the Riverside Police Department a year later. In the wake of national protests against police violence in 2020, Colorado, Virginia, and Nevada passed similar legislation aimed at combating systemic police misconduct. With this newfound authority, Colorado Attorney General Phil Weiser opened a pattern-or-practice investigation into the Aurora Police Department following the death of Elijah McClain. Similarly, Virginia Attorney General Mark Herring announced that he was investigating patterns or practices of misconduct within the Windsor Police Department after its officers pepper sprayed a Black U.S. Army medic in uniform while holding him at gunpoint during a traffic stop.

What are some common misconceptions about pattern-or-practice investigations?

Critics of pattern-or-practice investigations have argued that the resulting police reform agreements tie the hands of police officers and therefore undermine public safety. But research suggests the opposite to be true. For example, a study from the Harvard Kennedy School found that Los Angeles experienced lower crime rates and a higher quality of enforcement activity after its police department implemented a consent decree.

While some opponents point to data showing crime spikes in certain jurisdictions immediately after they entered into reform agreements, such increases have been temporary and diminished over time. In fact, the Center for American Progress found that in all 10 analyzed jurisdictions that fulfilled a reform agreement, violent crime rates declined in the years thereafter. Moreover, research from the University of Pennsylvania found that the use of consent decrees—when accompanied by court-appointed monitoring—was linked to a 29 percent reduction in officer-related fatalities.

Consent decrees do not target a few 'bad actors,' but rather departments with systemic and often long patterns of civil rights and other constitutional abuses or ingrained problems that undermine the effectiveness of law enforcement, the strength of police confidence and community relations, and the achievement of justice. Detroit Board of Police Commissioners

Kenny Lo is a former research associate for Criminal Justice Reform at the Center for American Progress.

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Kenny Lo

Research Associate

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