39 U.S.C. § 2605
Suits to recover wrongful or fraudulent payments
The Postal Service shall request the Attorney General to bring a suit to recover with interest any payment made from moneys of, or credit granted by, the Postal Service as a result of—
(1)
mistake;
(2)
fraudulent representations;
(3)
collusion; or
(4)
misconduct of an officer or employee of the Postal Service.
( Pub. L. 91–375 , Aug. 12, 1970 , 84 Stat. 745 .)