U.S. Attorney General Loretta Lynch arrives for a press conference at the Department of Justice December 7, 2015 in Washington, DC. Lynch announced a Justice Department investigation into the practices of the Chicago Police Department during the press conference.

U.S. Attorney General Loretta Lynch arrives for a press conference at the Department of Justice December 7, 2015 in Washington, DC. Lynch announced a Justice Department investigation into the practices of the Chicago Police Department during the press conference.

*The Chicago Police department is the latest target of the U.S.  Justice Dept.

At issue – patterns of racial disparity in the use of force by Chicago police officers. The entire department will be investigated as part of a wide-ranging probe that could lead to calls for sweeping changes, U.S. Attorney General Loretta Lynch announced Monday.

The investigation comes nearly two weeks after the release of a video showing a white Chicago police officer shooting a black teenager 16 times and ahead of the expected release of similar footage in another death at the hands of an officer.

The investigation, which is separate from an existing federal investigation into last year’s shooting death of 17-year-old Laquan McDonald, also will review how the department disciplines officers and handles misconduct accusations.

Justice Department officials say they use such patterns-and-practices investigations to identify systemic failings in troubled police departments and to improve trust between police and the communities they serve.

“This mistrust from members of the community makes it more difficult to gain help with investigations, to encourage victims and witnesses of crimes to speak up, and to fulfill the most basic responsibilities of public safety officials,” Lynch said. “And when suspicion and hostility is allowed to fester, it can erupt into unrest.”

The civil rights probe follows recent ones in Baltimore and Ferguson, Missouri, and comes as the police department and Mayor Rahm Emanuel are under intense scrutiny over their handling of the October 2014 death of McDonald. Officer Jason Van Dyke was charged with first-degree murder Nov. 24, more than a year after the killing and just hours before the release of police dashboard camera footage showing the officer shooting the teenager.

Emanuel, who initially said a federal civil rights investigation would be “misguided” but later reversed course, said in a news release after Lynch’s announcement that his goal is to create a stronger and better police force “that keeps the community safe while respecting the civil rights of every Chicagoan.”

The Justice Department has opened 23 investigations of police departments since the start of the Obama administration.

If the Justice Department finds systemic violations, the investigations typically result in court-enforceable agreements between the federal government and the community that serve as blueprints for change and are overseen by an independent monitor. The federal government has the option of suing a police department that is unwilling to make changes.

Also Monday, Cook County State’s Attorney Anita Alvarez, criticized for not filing charges earlier in the McDonald case, will speak about the killing of another young black man by city police. Authorities say Ronald Johnson, 25, pointed a gun at police before an officer shot and killed him on Oct. 12, 2014. His mother, Dorothy Holmes, said that wasn’t the case and that her son was running away from police. Emanuel has said the city would release video this week of Johnson’s shooting.