WASHINGTON — The Justice Department plans to launch an investigation into the patterns and practices of the Chicago Police Department, a wide-ranging review similar to those that scrutinized the police departments in Ferguson, Missouri, and Baltimore, according to several law enforcement officials.

The civil probe comes as Chicago continues to grapple with protests after the release of a video showing the police shooting of Laquan McDonald, which prompted murder charges for the officer involved and the resignation of the city’s police chief. The Justice Department is already investigating the McDonald shooting, but this new investigation by the department’s civil rights division would focus on the police department’s practices broadly to determine whether any of them contribute to civil rights violations.

Mayor Rahm Emanuel called the possibility of a civil rights investigation “misguided” last week. But, a day later, he said he would welcome such a probe.

Emanuel has come under fire for his administration’s handling of the McDonald video, specifically for fighting its release for more than a year, which some have suggested was a politically motivated decision meant to insulate the mayor from backlash while he was locked in a tight re-election effort. One week after the McDonald video was released, Emanuel fired Police Superintendent Garry F. McCarthy.

“I welcome the engagement of the Justice Department,” Emanuel said Thursday. “We have a long road ahead of us as a city, and I welcome people from many views to help us do what exactly we need to do.”

On the same day that McCarthy was fired, Illinois Attorney General Lisa Madigan wrote a letter to the Justice Department urging them to open an investigation into the police department.

“The McDonald shooting is shocking, and it highlights serious questions about the historic, systemic use of unlawful and excessive force by Chicago police officers and the lack of accountability for such abuse by CPD,” Madigan wrote.

Under Obama, Attorneys General Loretta Lynch and her predecessor, Eric Holder, have used patterns-and-practices investigations to aggressively probe police departments for potential constitutional violations, investigating dozens of departments since 2009 .

Congress empowered the federal government to conduct such investigations in the aftermath of the 1991 videotaped beating of Rodney King by Los Angeles officers and the riots that followed. A law passed in 1994 gave Justice the power to investigate and force systemic changes to local police departments – and to sue the departments if they do not comply.

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