Tavores Henderson, who stands accused of running over Sgt. Kaila Sullivan and killing her, attended his first court appearance for capital murder charges wearing Sgt. Sullivan's handcuffs.
Two other officers were also wounded when they responded to a domestic disturbance.
Fox Lake police lieutenant Joe Gliniewicz was laundering money from police funds.
It was biggest protest since 25-year-old Freddie Gray died last Sunday.