Mich. Comp. Laws § 41.62
The supervisor shall preserve and keep the books, assessment rolls, and other papers belonging to the supervisor's office in a safe and suitable place, but not where the books, assessment rolls, and other papers will be exposed to an unusual hazard from fire or theft. The supervisor shall deliver the books, assessment rolls, and other papers on demand to his or her successor in office. The books, assessment rolls, papers, and any other writing prepared, owned, used, in the possession of, or retained by the supervisor in the performance of an official function shall be made available to the public in compliance with the freedom of information act, Act No. 442 of the Public Acts of 1976, being sections 15.231 to 15.246 of the Michigan Compiled Laws.
MCL 41.62