28 U.S.C. § 546 : US Code - Section 546: Vacancies

      (a) Except as provided in subsection (b), the Attorney General
    may appoint a United States attorney for the district in which the
    office of United States attorney is vacant.
      (b) The Attorney General shall not appoint as United States
    attorney a person to whose appointment by the President to that
    office the Senate refused to give advice and consent.
      (c) A person appointed as United States attorney under this
    section may serve until the earlier of - 
        (1) the qualification of a United States attorney for such
      district appointed by the President under section 541 of this
      title; or
        (2) the expiration of 120 days after appointment by the
      Attorney General under this section.

      (d) If an appointment expires under subsection (c)(2), the
    district court for such district may appoint a United States
    attorney to serve until the vacancy is filled. The order of
    appointment by the court shall be filed with the clerk of the
    court.