19 CFR 162.21 - Responsibility and authority for seizures.
(a) Seizures by Customs officers. Property may be seized, if available, by any Customs officer who has reasonable cause to believe that any law or regulation enforced by Customs and Border Protection or Immigration and Customs Enforcement has been violated, by reason of which the property has become subject to seizure or forfeiture. This paragraph does not authorize seizure when seizure or forfeiture is restricted by law or regulation (see, for example, § 162.75), nor does it authorize a remedy other than seizure when seizure or forfeiture is required by law or regulation. A receipt for seized property shall be given at the time of seizure to the person from whom the property is seized.
(b) Seizure by persons other than Customs officers. The port director may adopt a seizure made by a person other than a Customs officer if such port director has reasonable cause to believe that the property is subject to forfeiture under the Customs laws.
(c) Seizure by State official. If a duly constituted State official has seized any merchandise, vessel, aircraft, vehicle, or other conveyance under provisions of the statutes of such State, such property shall not be seized by a Customs officer unless the property is voluntarily turned over to him to be proceeded against under the Federal statutes.