Michigan Compiled Laws, Chapter 38. Civil Service and Retirement § 38.562

Sec. 12. (1) The membership of the retirement system created by a municipality affected by this act shall include each police officer and fire fighter employed by a municipality. A police officer or fire fighter, who is a member of the retirement system and who is transferred from the classification of a police officer or fire fighter to a civilian position within the police or fire department or who is transferred from the police or fire department of the municipality to another department of the municipality by an officer or body of the municipality authorized to make the transfer, shall continue as a member of this retirement system covering the police officers and fire fighters, and shall be subject to the provisions of the retirement system. If the officers and employees of the department to which the person is transferred are covered by an annuity pension or retirement system to which the municipality makes contributions and the person transferred becomes entitled to membership in that system, the person shall cease to be a member of this police officer and fire fighter retirement system.

(2) The membership of the retirement system shall not include a volunteer fire fighter, a privately employed police officer or fire fighter, a person temporarily employed during an emergency, a civilian employee of a police and fire department, or a person participating in a transitional public employment program, except as provided in subsection (1) and section 6c.  1