I have completed all the forms for my expungement in Illinois?

but I am stuck on who to send them to. I need to file at the 3rd district (Rolling Meadows) so I have addressed to the states attorney at the rolling meadows courthouse. The arresting agency was the Norridge Police Dept and Illinois State Police is already pre-filled and the 4th says "Chief Legal Officer of the unit of local government that arrested you": HELP - I do not know who this is or what address to put down! Where do I locate this information??? Please help.