Mich. Comp. Laws § 776.18
The prosecuting attorney may procure the assistance in the trial of any person charged with a felony as he or she considers necessary. The prosecuting attorney may appoint an assistant to perform his or her duties during a period when the prosecuting attorney is unable to perform those duties. An assistant appointed under this section shall be paid reasonable compensation as determined by the board of supervisors or the board of county auditors, as applicable, for those services. No person shall be employed or appointed as assistant prosecutor who is interested as an attorney or otherwise in a case involving the same facts or circumstances involved in a case to be conducted or tried by the assistant prosecutor or who has received any compensation from any person with an interest in those cases.
MCL 776.18