735 ILCS 5/10-111: Manner of service.

Service shall be made by leaving a copy of the order with the person to whom it is directed, or with any of his or her under officers who may be at the place where the prisoner is detained; or if he or she can not be found, or has not the person imprisoned or restrained in custody, the service may be made upon any person who has the person in custody with the same effect as though he or she had been made a defendant therein.