CHICAGO (CBS) — A group of retired black Chicago police officers has joined the call for a federal civil rights investigation of the Chicago Police Department’s practices, saying the Laquan McDonald case illustrates a problem with racism on the police force.

Retired Chicago Police Sgt. Michael Davis told the story of when he patrolled Englewood with a white partner many years ago.

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“We would drive around, and he would speak out of the window, ‘Hey, a******, get over here!’” he said.

Davis said, while most cops are good, that kind of things remain a problem, and worse. He said the McDonald case is just one example of deep-rooted problems at the department.

“There are some additional shootings in this city that are worse than the shooting of Laquan,” he said. “The misconduct that you see has been going on for years in this city. The thing that is different now is cameras.”

Retired officer Pat Hill said she and others have done a disservice to young people by telling them things have changed.

“The murder of Laquan McDonald is really synonymous to the murder of Emmett Till,” she said, referring to the infamous 1955 lynching of a 14-year-old black boy in Mississippi, after he reportedly whistled at a white woman.

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Retired police officer Richard Wooten said they support protesters who have criticized the city’s handling of the McDonald case, but he insisted the department is not inherently corrupt.

“Every bin has its bad apples. So don’t think that the Chicago Police Department’s corrupt. The police department’s just like any other profession, okay? You have human beings operating it,” he said.

That said, he and other retired officers want the U.S. Justice Department to launch a civil rights investigation of the department’s policies and practices in light of the McDonald case.

Officer Jason Van Dyke has been charged with first-degree murder in McDonald’s death. Dashboard camera video of the shooting shows Van Dyke shooting McDonald 16 times on Oct. 20, 2014.

The city fought for more than a year to keep the video under wraps, and critics have accused Mayor Rahm Emanuel, former Police Supt. Garry McCarthy, and Cook County State’s Attorney Anita Alvarez of a cover-up for waiting so long to release the video and bring charges against Van Dyke, who was not charged until more than a year after the shooting.

Illinois Attorney General Lisa Madigan announced Tuesday she was requesting the Justice Department launch a civil rights investigation of the Chicago Police Department.

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Mayor Emanuel has said a civil rights investigation of CPD would be “misguided,” given that federal prosecutors already are investigating the McDonald case.