Ill. Admin. Code tit. 89, § 330.3 – Conducting the Investigation

a) Upon receipt of a written court order, the Department will perform a child custody investigation.
b) In child custody investigations Department staff will interview both parents. The Department will also interview children who are able to understand the proceedings as well as other persons who may have information about the child and the custodial arrangement. Primary consideration shall be given to investigating the following:
1. 1) the wishes of the parent(s) regarding the child's custody;
2. 2) the wishes of the child regarding who his custodian should be;
3. 3) the child's interaction and inter-relationship with each of his parent(s), his siblings and others who may significantly affect his best interest; and
4. 4) the child's adjustment to his home, school and community when living with each of the parents.
c) In child custody investigations the Department will refer the child to professional personnel (i.e., physician, psychiatrist, psychologist) only upon an order of the court. The Department may, without the prior consent of the parent(s) or custodian, consult with any person who may have information about the child and the custodial arrangement. These consultations may include medical or school personnel who have served the child in the past. However, the consent of a child 16 years of age or older shall be obtained prior to any such consultations, unless the court finds that the child lacks the mental capacity to consent.