Mich. Comp. Laws § 48.37
The county treasurer shall appoint a deputy, who, in the absence of the treasurer from the office, or in case of a vacancy in the office, or a disability of the treasurer to perform the duties of the office, may perform all the duties of the office of treasurer, until the vacancy is filled or the disability is removed. The county treasurer may revoke those appointments at any time. The deputy shall qualify by taking the constitutional oath of office and filing a bond, if the county board of commissioners determines that an individual bond is necessary. The treasurer may employ personnel necessary and approved by the county board of commissioners. In a county having a civil service, employment of personnel shall be in accordance with Act No. 370 of the Public Acts of 1941, as amended, being sections 38.401 to 38.428 of the Michigan Compiled Laws. All appointments and revocations of appointments shall be in writing. A treasurer shall not be responsible for the acts, defaults, and misconduct in office of a deputy or any other employee in the treasurer's office accruing without the knowledge or negligence of the treasurer. Each employee, before entering upon the duties of office, shall execute and file an individual bond, for the faithful performance of duties in the amount, form, and manner prescribed by the county board of commissioners, if the county board of commissioners determines that an individual bond is necessary. The deputy or other employee shall be liable for the deputy's or employee's acts, defaults, and misconduct in office in the same manner as the treasurer or the treasurer's executors and administrators would otherwise be liable, and actions for those acts, defaults, and misconduct shall be prosecuted directly against the deputy or other employee, and the appropriate surety.
MCL 48.37