(1) Unless sooner released, a minor requiring authoritative intervention, taken into temporary custody, must be brought before a judicial officer within 48 hours, exclusive of Saturdays, Sundays and court-designated holidays, for a shelter care hearing to determine whether the minor shall be further held in custody.
     (2) If the probation officer or such other public officer designated by the court determines that the minor should be retained in custody, the probation officer or such other public officer designated by the court shall cause a petition to be filed as provided in Section 3-15 of this Act, and the clerk of the court shall set the matter for hearing on the shelter care hearing calendar. When a parent, guardian, custodian or responsible relative is present and so requests, the shelter care hearing shall be held immediately if the court is in session, otherwise at the earliest feasible time. The petitioner through counsel or such other public officer designated by the court shall insure notification to the minor’s parent, guardian, custodian or responsible relative of the time and place of the hearing by the best practicable notice, allowing for oral notice in place of written notice only if provision of written notice is unreasonable under the circumstances.
     (3) The minor must be released from custody at the expiration of the 48 hour period, if not brought before a judicial officer within that period.