Illinois’ top prosecutor on Tuesday asked the U.S. Department of Justice to investigate whether Chicago police practices violate federal law. The request by Illinois Attorney General Lisa Madigan comes on the same day that Chicago’s police chief was fired following the release of dash-cam video that showed an officer fatally shoot 17-year-old Laquan McDonald last year. “The shocking death of Laquan McDonald is the latest tragedy in our city that highlights serious questions about the use of unlawful and excessive force by Chicago police officers and the lack of accountability for such abuse,” Madigan said in a statement.