19 U.S. Code § 1615 - Burden of proof in forfeiture proceedings
In all suits or actions (other than those arising under section 1592 of this title) brought for the forfeiture of any vessel, vehicle, aircraft, merchandise, or baggage seized under the provisions of any law relating to the collection of duties on imports or tonnage, where the property is claimed by any person, the burden of proof shall lie upon such claimant; and in all suits or actions brought for the recovery of the value of any vessel, vehicle, aircraft, merchandise, or baggage, because of violation of any such law, the burden of proof shall be upon the defendant: Provided, That probable cause shall be first shown for the institution of such suit or action, to be judged of by the court, subject to the following rules of proof:
(1) The testimony or deposition of the officer of the customs who has boarded or required to come to a stop or seized a vessel, vehicle, or aircraft, or has arrested a person, shall be prima facie evidence of the place where the act in question occurred.
(2) Marks, labels, brands, or stamps, indicative of foreign origin, upon or accompanying mechandise  or containers of merchandise, shall be prima facie evidence of the foreign origin of such merchandise.
(3) The fact that a vessel of any description is found, or discovered to have been, in the vicinity of any hovering vessel and under any circumstances indicating contact or communication therewith, whether by proceeding to or from such vessel, or by coming to in the vicinity of such vessel, or by delivering to or receiving from such vessel any merchandise, person, or communication, or by any other means effecting contact or communication therewith, shall be prima facie evidence that the vessel in question has visited such hovering vessel.
 So in original. Probably should be “merchandise”.
Source(June 17, 1930, ch. 497, title IV, § 615,46 Stat. 757; Aug. 5, 1935, ch. 438, title II, § 207,49 Stat. 525; Pub. L. 95–410, title I, § 110(d),Oct. 3, 1978, 92 Stat. 896; Pub. L. 98–473, title II, § 321,Oct. 12, 1984, 98 Stat. 2056; Pub. L. 98–573, title II, § 213(a)(13),Oct. 30, 1984, 98 Stat. 2987.)
Provisions somewhat similar to those in this section were contained in act Oct. 3, 1913, ch. 16, § III, T, 38 Stat. 189, the provisions of which were originally enacted in the Customs Administrative Act of June 10, 1890, ch. 407, § 21,26 Stat. 140, and reenacted by the Payne-Aldrich Tariff Act of Aug. 5, 1909, ch. 6, § 28,36 Stat. 101, and amended by the 1913 act. Section III of the 1913 act was superseded by act Sept. 21, 1922, ch. 356, title IV, § 615,42 Stat. 987, and was repealed by section 643 thereof. Section 615 of the 1922 act was superseded by section 615 of act June 17, 1930, comprising this section, and repealed by section 651(a)(1) of the 1930 act.
1984—Pub. L. 98–573and Pub. L. 98–473inserted reference to aircraft in provisions preceding par. (1) and in par. (1).
1978—Pub. L. 95–410inserted “(other than those arising under section 1592 of this title)” after “In all suits or actions”.
1935—Act Aug. 5, 1935, inserted a comma in place of a period at the end, inserted “subject to the following rules of proof”, and added subds. (1) to (3).
Effective Date of 1984 Amendment