§ 21 — Stolen Or Counterfeit Nature Of Property For Certain Crimes Defined

(a) Wherever in this title it is an element of an offense that— (1) any property was embezzled, robbed, stolen, converted, taken, altered, counterfeited, falsely made, forged, or obliterated; and (2) the defendant knew that the property was of such character; (b) For purposes of this section, the term “official representation” means any representation made by a Federal law enforcement officer (as defined in section 115) or by another person at the direction or with the approval of such an officer.