28 U.S.C. § 567: Collection of fees; accounting

(a) Each United States marshal shall collect, as far as possible, his lawful fees and account for the same as public moneys. (b) The marshal’s accounts of fees and costs paid to a witness or juror on certificate of attendance issued as provided by sections 1825 and 1871 of this title may not be reexamined to charge him for an erroneous payment of the fees or costs.