Is there authority to apply the protection of the Fourth Amendment to a civil forfeiture proceeding?

Franks provides that if a criminal defendant makes a substantial preliminary showing that a false statement was knowingly, intentionally or recklessly made in order to obtain a search warrant and if the false statement was necessary to establish probable cause, the defendant is entitled to an evidentiary hearing to determine if the warrant was obtained improperly. There is authority for applying the protection of the Fourth Amendment to a civil forfeiture proceeding. See One 1958 Plymouth Sedan v. Pennsylvania, 380 U.S. 693, 696, 85 S.Ct. 1246, 1248, 14 L.Ed.2d 170 (1965) (evidence derived from search in violation of Fourth Amendment is inadmissible in a civil forfeiture proceeding); Boyd v. United States, 116 U.S. 616, 634, 6 S.Ct. 524, 534, 29 L.Ed. 746 (1886) (protections of Fourth Amendment apply in civil forfeiture proceeding). However, since on appeal the government assumed arguendo the applicability of Franks to this proceeding, we likewise make that assumption without needing to decide the issue.