28 U.S.C. § 537 : US Code - Section 537: Expenses of unforeseen emergencies of a confidential character

Search 28 U.S.C. § 537 : US Code - Section 537: Expenses of unforeseen emergencies of a confidential character

Appropriations for the Federal Bureau of Investigation are
available for expenses of unforeseen emergencies of a confidential
character, when so specified in the appropriation concerned, to be
spent under the direction of the Attorney General. The Attorney
General shall certify the amount spent that he considers advisable
not to specify, and his certification is a sufficient voucher for
the amount therein expressed to have been spent.