Attorney General Merrick Garland announced Monday that the Justice Department will open a civil investigation of the Louisville Metro Police Department, 13 months after the shooting death of Breonna Taylor, a Black woman whose killing was among the flash points that sparked mass social-justice protests across the nation last summer.

Garland said the federal “pattern or practice” probe will seek to determine whether the Louisville police have engaged in systemic abuses and unlawful tactics with little accountability — marking the second time in five days he has sought to use federal power to examine a local law enforcement agency’s use of deadly force. Last week, he said the federal agency would investigate the Minneapolis Police Department after former officer Derek Chauvin was found guilty in the killing of George Floyd, a Black man, last May.

The twin announcements reflected the urgency with which the Biden administration is aiming to confront abusive policing amid an outcry from civil rights groups. Although the Chauvin verdict offered a measure of accountability, advocates have pointed to the fatal police shootings this month of Black men in Brooklyn Center, Minn., and Elizabeth City, N.C., as evidence that broad-reaching reforms are necessary in departments across the country.

President Biden is expected to address the issue in his first speech to a joint session of Congress on Wednesday, White House aides said.

The Trump administration sought to end federal investigations of local police departments, which had been used with increasing frequency in the final years of President Barack Obama’s tenure. But Garland has moved quickly to restore the Justice Department’s ability to wield federal authority to force reforms.

“I don’t know whether the administration is intentionally trying to be dramatic in signaling that the Civil Rights Division is back in business by announcing these investigations so quickly after each other — but that’s certainly the message it sends,” said Christy E. Lopez, who oversaw several pattern-or-practice investigations as deputy chief of the Justice Department’s special litigation section in the Obama administration. “I think that’s a positive thing.”

Justice Department officials said the Louisville investigation will be separate from an ongoing criminal civil rights probe into Taylor’s death. The broader civil investigation, Garland said, will seek to determine whether the city’s police force engages in unreasonable force, unconstitutional searches and seizures, and unlawful executions of search warrants on private homes.

It also will examine how Louisville police tactics affect racial groups and whether the department consistently provides services required under the Americans With Disabilities Act, he said.

“All of these steps will be taken with one goal in mind: to ensure that policing policies and practices are constitutional and lawful,” Garland said. “That is the same goal as that of our investigation in Minneapolis and of every pattern-or-practice investigation that the department undertakes.”

Public officials in Louisville and Minneapolis have welcomed the Justice Department probes and pledged to cooperate. At a news conference, Louisville Mayor Greg Fischer, Police Chief Erika Shields and other city leaders said they hoped the federal investigation would validate reforms the department has implemented since Taylor’s death.

Taylor, 26, was shot and killed in Louisville in March 2020 after three White plainclothes officers forced entry to her apartment during an apparent investigation into drug dealing. Taylor’s boyfriend fired a warning shot, prompting the officers to respond with 32 shots, including six that struck Taylor.

The Louisville police department fired three officers — one of whom faces three counts of wanton endangerment in the first degree for firing bullets that penetrated an adjacent apartment — and the city agreed to pay Taylor’s family $12 million. None of the officers have been charged in Taylor’s death.

A senior Justice Department official, speaking on the condition of anonymity to discuss a sensitive matter, said the investigation was prompted not only by Taylor’s killing but also by other information that has surfaced publicly about how the Louisville police department operates.

In cases where the Justice Department finds a pattern or practice of violating constitutional rights, cities often will negotiate how to remedy the problems, either agreeing to self-corrective steps or the appointment of an outside monitor.

In his remarks, Garland sought to strike a balance between recognizing the difficult circumstances that police are facing and the need to ensure justice for communities that have been routinely mistreated by abusive officers.

“We are uniquely aware of the challenges faced by those who serve as police officers. We see their commitment firsthand every day, and we recognize the complex issues that make their already difficult jobs even harder,” Garland said. “The Justice Department is also charged with ensuring that the constitutional and federal statutory rights of all people are protected.”

Civil rights advocates, who during the mass protests that erupted after Floyd’s death demanded accountability for Taylor and other Black people killed by police, applauded Garland’s announcement.

“The relationship between law enforcement and our community has been deeply fractured and shattered by the lack of trust and the little to no accountability enforced when police commit a crime,” NAACP President Derrick Johnson said in a statement after Garland’s announcement. “For far too long, killings at the hands of police have only led to one hashtag after another. But true justice comes with accountability and action.”

The Obama administration opened 25 investigations of local law enforcement agencies and enforced 14 court-approved consent decrees mandating changes, including in Baltimore, Chicago, New Orleans and Ferguson, Mo. But such cases often take months to complete, experts said, and broad reforms can be slow to take hold even if the Justice Department pursues a negotiated settlement with a local law enforcement agency.

Former Obama administration officials called the settlements effective in reducing excessive force. But they acknowledged the limitations of federal authority in meeting the expectations of community groups that have called for defunding police and enacting sweeping cultural changes in local departments.

Although Louisville’s police department has sought to improve relations with community groups, the effort has been complicated by the January hiring of Shields, who had resigned as chief of the Atlanta Police Department six months earlier after officers fatally shot a Black man in a fast-food parking lot. Community leaders have criticized the hiring as tone deaf.

Garland was joined at his announcement by Deputy Attorney General Lisa Monaco and Associate Attorney General Vanita Gupta, who helped oversee several Justice Department investigations of police agencies during the Obama administration.

The three of them had met Friday with a small group representing law enforcement officials to discuss a number of issues, including the Justice Department’s use of federal investigations and consent decree settlements.

Police agencies have expressed concerns that local departments enter into agreements overseen by monitors whose tenures are not clearly defined and often stretch on indefinitely, years after the agreements are negotiated. In a memo this month, Garland said that Gupta would oversee a review of the use of monitors.

“It’s not the investigation; it’s the process — the role of the monitor — which we have been complaining about for years,” said Chuck Wexler, executive director of the Police Executive Research Forum.

“The message I got from that meeting was, ‘Look, we want to engage with you guys — not simply investigate,’ ” Wexler said. “It was a very positive meeting.”

Devlin Barrett contributed to this report.

Correction: A previous version of this report said one Louisville police officer involved in the shooting of Breonna Taylor was fired. Two detectives also involved in the incident were fired in January.