Cleveland mounted police patrol the streets as protesters march out of the city following the not guilty verdict for Cleveland police officer Michael Brelo on manslaughter charges in Cleveland, Ohio, May 23, 2015. [Photo/Agencies]

Two other high-profile police-involved deaths still hang over the city: that of Tamir Rice, a 12-year-old black boy who was carrying a pellet gun at a playground when he was fatally shot by a white rookie patrolman Nov. 22, 2014, and that of 37-year-old Tanisha Anderson, a mentally ill woman who died of positional asphyxiation after officers took her to the ground and handcuffed her Nov. 12, 2014.

The investigation was the second time in recent years the Justice Department has taken the Cleveland police to task over the use of force. But unlike in 2004, when the agency left it up to local police to clean up their act, federal authorities intervened this time. Several other police departments in the country now operate under federal consent decrees that involve independent oversight.

The Justice Department has launched broad investigations into the practices of more than 20 police forces in the last five years, including agencies in Ferguson, Missouri, and, most recently, in Baltimore. Then-Attorney General Eric Holder said in December that the Justice Department was enforcing settlement agreements with roughly 15 police departments, including eight consent decrees.