28 USC § 520. Transmission of petitions in United States Court of Federal Claims or in United States Court of Appeals for the Federal Circuit; statement furnished by departments
(a) In suits against the United States in the United States Court of Federal Claims or in the United States Court of Appeals for the Federal Circuit founded on a contract, agreement, or transaction with an executive department or military department, or a bureau, officer, or agent thereof, or when the matter or thing on which the claim is based has been passed on and decided by an executive department, military department, bureau, or officer authorized to adjust it, the Attorney General shall send to the department, bureau, or officer a printed copy of the petition filed by the claimant, with a request that the department, bureau, or officer furnish to the Attorney General all facts, circumstances, and evidence concerning the claim in the possession or knowledge of the department, bureau, or officer.
(b) Within a reasonable time after receipt of the request from the Attorney General, the executive department, military department, bureau, or officer shall furnish the Attorney General with a written statement of all facts, information, and proofs. The statement shall contain a reference to or description of all official documents and papers, if any, as may furnish proof of facts referred to in it, or may be necessary and proper for the defense of the United States against the claim, mentioning the department, office, or place where the same is kept or may be secured. If the claim has been passed on and decided by the department, bureau, or officer, the statement shall briefly state the reasons and principles on which the decision was based. When the decision was founded on an Act of Congress it shall be cited specifically, and if any previous interpretation or construction has been given to the Act, section, or clause by the department, bureau, or officer, it shall be set forth briefly in the statement and a copy of the opinion filed, if any, attached to it. When a decision in the case has been based on a regulation of a department or when a regulation has, in the opinion of the department, bureau, or officer sending the statement, any bearing on the claim, it shall be distinctly quoted at length in the statement. When more than one case or class of cases is pending, the defense of which rests on the same facts, circumstances, and proofs, the department, bureau, or officer may certify and send one statement and it shall be held to apply to all cases as if made out, certified, and sent in each case respectively.