California Code, Family Code - FAM § 3133

If the district attorney represents to the court, by a written declaration under penalty of perjury, that a temporary custody order is needed to recover a child who is being detained or concealed in violation of a court order or a parent's right to custody, the court may issue an order, placing temporary sole physical custody in the parent or person recommended by the district attorney to facilitate the return of the child to the jurisdiction of the court, pending further hearings.  If the court determines that it is not in the best interest of the child to place temporary sole physical custody in the parent or person recommended by the district attorney, the court shall appoint a person to take charge of the child and return the child to the jurisdiction of the court.