In a case arising under this title or involving the Hague Convention on the Civil Aspects of International Child Abduction, the Attorney General may take any lawful action, including resort to a proceeding under this subtitle or any other available civil proceeding to locate a child, obtain the return of a child, or enforce a child custody determination if there is: an existing child custody determination; a request to do so from a court in a pending child custody proceeding; a reasonable belief that a criminal statute has been violated; or a reasonable belief that the child has been wrongfully removed or retained in violation of the Hague Convention on the Civil Aspects of International Child Abduction. The Attorney General acting under this section on behalf of the court may not represent any party.