A U.S. Justice Department investigation into the Memphis Police Department after the beating death of Tyre Nichols found a pattern of unlawful use of excessive force and discrimination against the Black residents of the majority-Black city in Tennessee.

The Memphis case is one of 12 similar investigations of state and local law enforcementagencies opened by the DOJ since April 2021.

Many have been in response to high-profile deaths at the hands of police, including George Floyd and Breonna Taylor. The five other completed investigations all found patterns of illegal police practices.

George Floyd’s murder in Minneapolis

George Floyd died in May 2020 after a white officer pinned his neck to the pavement in Minneapolis for 9½ minutes, despite the Black man’s pleas of “I can’t breathe.” The ensuing global protests, which turned violent at times, sparked a nationwide reckoning over racism and police misconduct. Officer Derek Chauvin was convicted of murder.

In June 2023, the DOJ issued a report saying the police department in Minneapolis engaged in a pattern of using excessive force and discrimination. The city agreed to resolve the findings through a consent decree with an independent monitor.

The aftermath of Breonna Taylor’s death 

Breonna Taylor was shot and killed in her home during a raid in March 2020. Federal and state prosecutors have said Jonathan Mattingly and Myles Cosgrove were justified in returning fire after Taylor’s boyfriend grabbed a handgun and shot Mattingly in the leg. Taylor’s boyfriend said he mistook the police for an intruder breaking in after midnight.

The two officers left the department years ago and were not charged with any crimes. Two other former Louisville officers have been accused in federal court of falsifying the Taylor warrant.

In March 2023, the DOJ issued findings that the Louisville Metro Police Department had a pattern of unlawful practices that included executing search warrants without knocking and announcing. The report acknowledged changes already made by Louisville police and identified additional remedial measures that were needed.

Scandals in Phoenix

In Phoenix, there wasn’t a single episode that led to the DOJ investigation. Instead it came after many smaller scandals. A 2020 case accusing 15 protesters of being in an anti-police gang had to be dismissed for lack of credible evidence; in 2017, a “challenge coin” was circulated among officers depicting a gas mask-wearing demonstrator getting shot in the groin with a projectile; and in June 2019, cell phone video emerged showing officers pointing guns when they confronted an unarmed Black couple with two small children they suspected of shoplifting.

This June, the Justice Department issued a report finding that the Phoenix Police Department had a pattern of several unlawful practices. They included unlawfully arresting homeless people and disposing of their belongings, the unjustified use of deadly force, and discrimination against Black, Hispanic and Native American people and those experiencing mental health crises.

City officials have said they are analyzing the report. They have also launched a new website describing the police department’s “road to reform” and what they are doing to reduce the number of use of force incidents.

Civil rights violations in Mississippi

The DOJ investigation of Lexington, Miss., followed a lawsuit by a civil rights group that accused police in this small, rural town of terrorizing Black residents by subjecting them to false arrests, excessive force and intimidation.

The report, released in September, said the Lexington Police Department “has created a system where officers can relentlessly violate the law.”

The department operates under an unconstitutional conflict of interest because it is partially funded by money raised through fines. Police routinely arrest people who cannot pay fines or who owe outstanding fines and people are jailed without prompt access to court and with no assessment of their ability to pay bail, the report found.

The city and police cooperated fully with the investigation and committed to working with the DOJ to address the violations.

Excessive force in Trenton, N.J.

In Trenton, N.J., the DOJ issued a report just last month that concluded officers in the state’s capital have a pattern of misconduct, including using excessive force and making unlawful stops. The report documents arrests without legal basis, officers escalating situations with aggression and unnecessary use of pepper spray.

Officials said the city has cooperated and will continue to cooperate with the DOJ. Trenton has so far disbanded two police department street units that officials said violated the constitution.

In Louisiana, the Justice Department announced a federal probe in 2022 following an Associated Press investigation into the deadly 2019 arrest of Ronald Greene and at least a dozen cases in which troopers or their bosses ignored or concealed evidence of beatings. Federal authorities were asked to investigate the Mount Vernon Police Department in a suburb of New York by the Westchester County district attorney, who suggested the department has a problem with illegal strip searches.

The Special Victims Division of the New York Police Department in under investigation for how it handles sexual assault crimes following years of complaints about the way investigators treat crime victims.

In Oklahoma, the DOJ is investigating whether the state, Oklahoma City and Oklahoma City police discriminate against mentally ill adults, including by institutionalizing them when they could be helped in community settings.

The torture of two black men by white sheriff’s officers in Mississippi led to a probe of the Rankin County Sheriff’s Department. Following an Associated Press investigation, five Rankin officers and one from another department were charged and sentenced to terms of 10 to 40 years.

In Massachusetts, federal prosecutors did not point to any specific episode that triggered their investigation into a possible pattern of excessive force and discriminatory policing. The probe followed a lawsuit filed by a Black man who said he was wrongfully charged with murder based on his race and fabricated evidence.