Mich. Comp. Laws § 168.961a

Sec. 961a. (1) Not later than the business day following the filing of a recall petition, the official with whom the recall was filed shall notify in writing the officer whose recall is sought that the recall petition has been filed. (2) An officer whose recall is sought may challenge the validity of the registration or the validity and genuineness of the signature of a circulator or person signing the recall petition. A challenge shall be in writing, specifying the challenged signature, and shall be delivered to the filing official within 30 days after the filing of the petitions. The officer whose recall is sought shall have not less than 8 days after the clerk has examined the signatures to check signatures on the original registration records. (3) Subject to subsections (4) and (5), a challenged signature shall be verified by the official with whom the recall was filed. (4) The qualified voter file may be used to determine the validity of a challenged petition signature appearing on a recall petition by verifying the registration of the signer. If the qualified voter file indicates that, on the date the elector signed the petition, the elector was not registered to vote, there is a rebuttable presumption that the signature is invalid. If the qualified voter file indicates that, on the date the elector signed the petition, the elector was not registered to vote in the city or township designated on the petition, there is a rebuttable presumption that the signature is invalid. (5) The qualified voter file shall be used to determine the genuineness of a challenged petition signature appearing on a recall petition. Signature comparisons shall be made with the digitized signature in the qualified voter file. If the qualified voter file does not contain a digitized signature of an elector, the official with whom the recall petition was filed shall compare the challenged signature to the signature on the master card.