The United States Justice Department has opened a civil rights investigation into the practices of state police in Louisiana, after several recent cases of police violence primarily targeting Black men drew condemnation and calls for accountability.

In a news conference on Thursday, Kristen Clarke, assistant attorney general for the department’s civil rights division, said the probe will seek to “determine whether the Louisiana State Police engages in a pattern or practice of violations of the Constitution or federal law”.

It will focus on two main issues, Clarke told reporters.

“First, whether the Louisiana State Police has a pattern or practice of using excessive force. And second, whether the Louisiana State Police engages in racially discriminatory policing practices against Black people and other people of colour,” she said.

The announcement comes as the United States continues to grapple with police violence against Black and other people of colour, a problem that has set off mass Black Lives Matter demonstrations since 2020.

In Louisiana, the deadly 2019 arrest of Ronald Greene, in particular, has spurred calls for justice from residents and civil rights groups.

An investigation by The Associated Press (AP) found that Greene’s arrest was among at least a dozen cases over the past decade in which Louisiana state police troopers or their bosses ignored or concealed evidence of beatings, deflected blame and impeded efforts to root out misconduct.

Dozens of current and former troopers said the beatings were countenanced by a culture of impunity, nepotism and, in some cases, outright racism.

By its own tally, 67 percent of state police uses of force in recent years were against Black people, who make up 33 percent of the state’s population.

Body-camera footage obtained by AP and released in May of last year showed Louisiana state troopers stunning, punching and dragging Greene as he apologised for leading them on a high-speed chase during the deadly arrest.

“I’m your brother! I’m scared!” Greene can be heard telling the troopers as he is jolted repeatedly with a stun gun before he even gets out of his car along a dark, rural road.

AP’s reporting also found that Louisiana police troopers have made a habit of turning off or muting body cameras during pursuits. When footage is recorded, the agency has routinely refused to release it.

A recently retired supervisor who oversaw a particularly violent clique of troopers told internal investigators last year that it was his “common practice” to rubber-stamp officers’ use-of-force reports without ever reviewing body-camera video.

In some cases, troopers omitted uses of force, such as blows to the head from official reports, and in others, troopers sought to justify their actions by claiming suspects were violent, resisting or escaping — all of which were contradicted by video footage.

On Thursday, the American Civil Liberties Union (ACLU) of Louisiana, which had called on the Justice Department to launch an investigation into state police, welcomed the department’s announcement.

Executive Director Alanah Odoms said in a statement that ACLU-Louisiana had documented more than a dozen cases of “excessive force and constitutional rights violations against Black and Brown Louisiana citizens in the last five years alone”.

“We also documented discriminatory training practices, a culture of racism within the agency, racial violence directed at the community, and a dangerous cone of silence that inhibits transparent and lawful disclosure of evidence. This systemic misconduct was blessed by top brass at the Louisiana State Police,” Odoms said.

“This commitment by AAG Clarke and the DOJ to identify and remedy systemic misconduct symbolizes far more than a small step, it is a huge leap in furtherance of justice for Louisianans whose rights have been violated by this cruel and corrupt agency.”

Clarke at the Justice Department said the civil “pattern-or-practice” probe is aimed at driving needed reforms, if necessary by suing to implement a federal consent decree.

She added that Governor John Bel Edwards and the head of the Louisiana State Police, Lamar Davis, have pledged their cooperation. The state police did not respond to requests for comment on Thursday from AP.