Any vessel built, purchased, fitted out in whole or in part, or held for the purpose of being employed in the commission of any piratical aggression, search, restraint, depredation, or seizure, or in the commission of any other act of piracy, as defined by the law of nations, shall be liable to be captured and brought into any port of the United States if found upon the high seas, or to be seized if found in any port or place within the United States, whether the same shall have actually sailed upon any piratical expedition or not, and whether any act of piracy shall have been committed or attempted upon or from such vessel or not; and any such vessel may be adjudged and condemned, if captured by a vessel authorized as mentioned in section 386 of this title to the use of the United States, and to that of the captors, and if seized by a collector, surveyor, or marshal, then to the use of the United States.
(R.S. § 4297.)