Investigation by disinterested person; custody; guardianship

(a) The probation service or an authorized agency or disinterested person is authorized to, and at the request of the court, shall interview such persons and obtain such data as will aid the court in: (1) determining custody in a proceeding under section 467 or 651 of the Family Court Act; (2) exercising its power under section 661 of the Family Court Act to appoint a guardian of the person of a minor under the jurisdiction of the court. (b) The written report of the investigation conducted pursuant to subdivision (a) of this section shall be submitted to the court within 30 days from the date on which it was ordered, or earlier as the court may direct, unless, for good cause, the court shall grant an extension for a reasonable period of time not to exceed an additional 30 days.