18 U.S.C. § 1703 : US Code - Section 1703: Delay or destruction of mail or newspapers

      (a) Whoever, being a Postal Service officer or employee,
    unlawfully secretes, destroys, detains, delays, or opens any
    letter, postal card, package, bag, or mail entrusted to him or
    which shall come into his possession, and which was intended to be
    conveyed by mail, or carried or delivered by any carrier or other
    employee of the Postal Service, or forwarded through or delivered
    from any post office or station thereof established by authority of
    the Postmaster General or the Postal Service, shall be fined under
    this title or imprisoned not more than five years, or both.
      (b) Whoever, being a Postal Service officer or employee,
    improperly detains, delays, or destroys any newspaper, or permits
    any other person to detain, delay, or destroy the same, or opens,
    or permits any other person to open, any mail or package of
    newspapers not directed to the office where he is employed; or
      Whoever, without authority, opens, or destroys any mail or
    package of newspapers not directed to him, shall be fined under
    this title or imprisoned not more than one year, or both.