Mich. Comp. Laws § 775.7
Whenever any person shall attend any court of record as a witness in behalf of the people of this state, upon request of the public prosecutor, or upon subpoena, or by virtue of a recognizance for that purpose, and it shall appear that such person has come from any other state or territory of the United States, or from any foreign country or that such person is poor, the court may, by an order to be entered on its minutes, direct the county treasurer of the county in which the court may be sitting, to pay such witness such sum of money as shall seem reasonable for his expenses; and no fees shall be allowed or paid to witnesses on the part of the people in any criminal proceeding or prosecution except as is provided in this section and act.
MCL 775.7