18 U.S.C. § 1469: Presumptions

(a) In any prosecution under this chapter in which an element of the offense is that the matter in question was transported, shipped, or carried in interstate commerce, proof, by either circumstantial or direct evidence, that such matter was produced or manufactured in one State and is subsequently located in another State shall raise a rebuttable presumption that such matter was transported, shipped, or carried in interstate commerce. (b) In any prosecution under this chapter in which an element of the offense is that the matter in question was transported, shipped, or carried in foreign commerce, proof, by either circumstantial or direct evidence, that such matter was produced or manufactured outside of the United States and is subsequently located in the United States shall raise a rebuttable presumption that such matter was transported, shipped, or carried in foreign commerce.