Mich. Comp. Laws § 750.506a: Prisoners committing offenses defined in MCL 750.81 to 750.86; penalties.

Sec. 506a.

If a person, lawfully imprisoned in a jail or other place of confinement established by law, for any crime or offense, or lawfully imprisoned in a jail or other place of confinement after being sentenced for a crime or offense and awaiting or in transit to or from a prison or other place of confinement, commits any offense defined in sections 81 to 86, the court may impose the appropriate penalties prescribed in sections 81 to 86 to run consecutively with any sentence which the person is already serving.

If a person, lawfully detained in a jail or other place of confinement established by law, and awaiting arraignment, examination, trial or sentencing for any crime or offense, commits a subsequent offense defined in sections 81 to 86, if convicted of the crime or offense for which he was detained at the time he committed the subsequent offense, any sentences imposed for conviction of the prior offense and for conviction of the subsequent offense under sections 81 to 86 may run consecutively.