CHICAGO (CBS) — Members of the U.S. Justice Department were in Chicago on Wednesday to begin a civil rights investigation of the Chicago Police Department’s use of force.

Those involved in the investigation arrived at Chicago Police Headquarters around noon and left, about two-and-a-half hours later. It’s the first step in what’s likely to be a prolonged investigation of the CPD’s policies and procedures.

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U.S. Attorney Zach Fardon was tight lipped when leaving CPD headquarters this afternoon. Fardon and representatives from the Department of Justice met with the Chicago Police Department’s interim police superintendent, John Escalante and other top staff, at CPD headquarters.

“They’re just trying to get a sense of where this investigation is going so they can manage it and get it done in a reasonable amount of time,” said CBS 2 Legal Analyst Irv Miller.

The DOJ will interview city officials and the acting Superintendent John Escalante to compile their reports.

There will also be an analysis of police records, police stops, searches, citations and arrests.

“What they’re trying to do is see if there are any constitutional violations, policy violations, is there racial profiling within the Chicago Police Department?” Miller said.

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Mayor Rahm Emanuel says he’s also meeting with the Department of Justice.

“It is in our self-interest as a city that they’re here because the problems and challenges we have in a sense of police and community relations and changes we need are deep seeded,” Emanuel said. “They go way back.”

Escalante has said he and the Emanuel administration will select a senior commander to act as a liaison with the Justice Department during the probe.

The federal investigation is expected to take several months to complete. If the Justice finds systemic violations of federal law or the U.S. Constitution, the feds and the city would work out a detailed agreement on reforms.

Wednesday’s meeting with the Justice Department comes a day after Chicago aldermen held an extended public hearing on the fatal police shooting of 17-year-old Laquan McDonald.

Chicago’s top cop and the heads of agencies who police the police were all grilled by aldermen who themselves were feeling the heat over the use of deadly force.

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Aldermen introduced an ordinance requiring an annual four hour refresher course on the appropriate use of force, while also digging into the alleged code of silence. Escalante vowed to end it, while Fraternal Order of Police president Dean Angelo said it doesn’t exist.