Mich. Comp. Laws § 38.29

Sec. 29. Should a member die before his service retirement becomes effective, the accumulated contributions standing to his credit in the employees' savings fund, at the time of his death, shall be paid, except as otherwise provided in this act, to such person or persons as he shall have nominated by written designation duly executed and filed with the retirement board, or if there be no such designated person or persons, then to his legal representative.