To amend title 39, United States Code, to grant the United States Postal Service the authority to issue civil investigative demands, and for other purposes.

Authorizes the Postmaster General, whenever there is reason to believe that any person may be in possession, custody, or control of any documentary material or may have information relevant to an investigation of a matter arising under Federal postal law, to issue in writing and cause to be served upon such person before the commencement of a civil or criminal proceeding thereon, a civil investigative demand requiring such person to: (1) produce such documentary material for inspection and copying or reproduction; (2) answer in writing written interrogatories; (3) give oral testimony concerning such material or information; or (4) furnish any combination of such material, answers, or testimony.

Requires the Postmaster General to designate an agent to serve as custodian of documentary material, answers to interrogatories, and transcripts of oral testimony received, and such other necessary additional agents to serve as deputies to the custodian.

Authorizes the custodian to deliver to the Federal Trade Commission, upon written request, copies of such material, answers, or transcripts for use in connection with an investigation or proceeding under the Commission's jurisdiction to be used only in such manner and subject to such conditions as apply to the Postal Service.

Authorizes the Postal Service to file in the district court of the United States for any judicial district in which a person resides, is found, or transacts business and serve upon such person a petition for an order of such court for the enforcement of this Act if the person fails to comply with the civil investigative demand or whenever satisfactory copying or reproduction of any material cannot be done and the person refuses to surrender such material.

Exempts any documentary material, answers to written interrogatories, or transcripts of oral testimony provided pursuant to any demand issued under this Act from disclosure under the Freedom of Information Act.

Amends the Federal criminal code to impose a fine and up to five years' imprisonment upon anyone who intentionally obstructs any civil investigative demand made under the Antitrust Civil Process Act or provisions of this Act.

Revises prescribed civil penalties imposed for violation of specified postal law relating to false representations and lotteries. Requires such penalties to be paid into the Postal Service Fund (currently, the Treasury).

Revises provisions in the Federal criminal code relating to injunctions against fraud to allow the Attorney General to obtain temporary and preliminary injunctive relief upon a showing of probable cause to believe that a violation is occurring or is about to occur. Grants permanent relief when a violation is established by a preponderance of the evidence. Deems a violation to be occurring or about to occur for as long as victims of any such violation have not been redressed and the statute of limitations for such violation has not expired.