The top cop of Illinois wants the federal government to investigate the Chicago Police Department

The Department of Justice may be investigating Chicago PD, thanks to a pair of fresh scandals that have again placed the embattled police department under federal scrutiny.

Illinois Attorney General, Lisa Mandigan, is asking US Attorney General Loretta Lynch to look into the Chicago Police Department's practices - including use of deadly force, amid the continuing fallout from the shooting death of a teenager.

Police officer Jason Van Dyke is facing murder charges on accusations that he shot 17-year-old Laquan McDonald 16 times during an encounter in October last year.

In a letter to Attorney General Lynch Tuesday that was obtained by NBC News Chicago, Mandigan cited questions about the Chicago Police Department's "training, equipment and supervision of officers," and whether there's a "pattern or practice of discriminatory policing" as reasons for an investigation.

Mandigan says the McDonald shooting "highlights serious questions about the historic, systemic use" of excessive force by the Chicago Police Department.

Those claims have mobilized activists whose protests have indirectly led to Chicago Police Superintendent Gerry McCarthy's firing Tuesday - one week after graphic video of the Laquan McDonald shooting was released.

Questions remain about how the police department handled the McDonald shooting.

Most of those questions center around alleged inconsistencies between the official police report and what can be seen on the video - and an alleged second video from a nearby restaurant that is reportedly missing footage of the crucial moments before, during and after McDonald was shot.

Chicago's police department has been scrutinized for years over its law enforcement practices - including the operation of a massive secret police facility in which the thousands of people held there were reportedly treated and interrogated like terrorists.