William B. Caldwell brought this action under 42 U.S.C. § 1983 against various officials of the City of St. Louis and of the State of Missouri, seeking to enjoin the enforcement of Mo.Rev.Stat. § 195.145 (1969) and to recover damages for the alleged violation of his civil rights.1 Caldwell contended that this statute, which allows a civil action to be brought for the forfeiture of any motor vehicle which has been used for the transportation of controlled substances, violates his Fourth, Fifth and Fourteenth Amendment rights. The District Court dismissed Caldwell's complaint, and he appeals. We affirm in part and reverse in part.

Caldwell's automobile was seized by officers of the St. Louis Police Department on April 12, 1978, when the driver and other passengers, including Caldwell, were arrested for the illegal possession of a controlled substance and of a firearm. A civil action for the forfeiture of the automobile was subsequently brought in state court by the St. Louis Circuit Attorney under Mo.Rev.Stat. § 195.145 (1969). The driver of the vehicle at the time of its seizure was named as the defendant in that action. On May 5, 1978, Caldwell filed this action in federal court. Caldwell filed a motion to intervene in the state proceedings on May 8, 1978. That motion was granted approximately one month later.

On July 25, 1978, the District Court dismissed Caldwell's federal suit on various grounds. The court held that since there was an ongoing state court proceeding, federal abstention would be appropriate under Younger v. Harris, 401 U.S. 37, 91 S. Ct. 746, 27 L. Ed. 2d 669 (1971). The court thus dismissed Caldwell's claims for equitable relief.2 A motion to dismiss, which was made by the Attorney General, was also granted on the ground that Caldwell failed to allege any illegal acts on his part.3 The court granted motions for summary judgment, which were filed by the Chief of Police and by the members of the Board of Police Commissioners, on the ground that Caldwell failed to allege that these defendants committed any violation of his rights, or directed or acquiesced in the commitment of any such violation. The court also granted the motion for summary judgment made by the City of St. Louis on the ground that a municipality is not a "person" subject to a suit for damages under § 1983. The court specified in its order that the dismissal of the Chief of Police, the members of the Board of Police Commissioners and the City of St. Louis was with prejudice.

In Younger v. Harris, supra, the Supreme Court held that principles of equity, comity and federalism dictate that federal courts should generally refrain from enjoining ongoing state criminal proceedings, absent extraordinary circumstances where the danger of irreparable loss to the federal plaintiff is " 'both great and immediate.' " Id. at 46, 91 S. Ct. 746. A state's interest in the administration of its criminal laws may also make federal abstention appropriate where the state court proceedings are civil in nature but where they are in aid of and closely related to criminal statutes. Huffman v. Pursue, Ltd., 420 U.S. 592, 604, 95 S. Ct. 1200, 43 L. Ed. 2d 482 (1975). See also Juidice v. Vail, 430 U.S. 327, 335-336, 97 S. Ct. 1211, 51 L. Ed. 2d 376 (1977). In either case, federal-court interference with ongoing state court proceedings might not only constitute undue interference with legitimate state activities, but may also be interpreted " 'as reflecting negatively upon the state courts' ability to enforce constitutional principles.' " Huffman v. Pursue, Ltd., supra, 420 U.S. at 604, 95 S. Ct. at 1208. Accord, Juidice v. Vail, supra, 430 U.S. at 336, 97 S. Ct. 1211.

We agree with the District Court that federal abstention under the Younger doctrine is appropriate in this case. The state forfeiture proceeding, which was initiated pursuant to the challenged statute and which was pending when Caldwell's federal suit was filed, is clearly in aid of and closely related to the enforcement of Missouri's criminal laws. The state's interest in such forfeiture proceedings is likely to be as great as its interest in any proceeding under its criminal laws. See Huffman v. Pursue, Ltd., supra, 420 U.S. at 604, 95 S. Ct. 1200. Caldwell's counsel conceded at oral argument that Caldwell's federal constitutional claims can be presented in the state court proceeding. See Juidice v. Vail, supra, 430 U.S. at 337, 97 S. Ct. 1211; Huffman v. Pursue, Ltd., supra, 420 U.S. at 594, 95 S. Ct. 1200. Since Caldwell has shown no exceptional circumstances which would prevent the presumptive application of the Younger doctrine, See Juidice v. Vail, supra, 430 U.S. at 337-338, 97 S. Ct. 1211, his equitable claims were properly dismissed.4

The principles of comity embodied in Younger also require the dismissal of Caldwell's damage claims. Caldwell's damage claims and his equitable claims are inextricably intertwined; both depend upon the constitutionality of the state forfeiture statute. If, in the course of adjudicating Caldwell's damage claims, a federal court were to rule that the statute is unconstitutional, substantial disruption of the state proceedings would result. See Martin v. Merola, 532 F.2d 191, 195 (2d Cir. 1976); Guerro v. Mulhearn, 498 F.2d 1249, 1253 (1st Cir. 1974). Compare Sartin v. Commissioner of Pub. Saf. of St. of Minn., 535 F.2d 430, 434 & n.8 (8th Cir. 1976) (action for damages in federal court could proceed where state judicial proceedings were closed). Under the narrow circumstances present here, we believe that Caldwell's damage claims should also be dismissed.5

Although we agree that Younger requires the dismissal of Caldwell's complaint, we reverse the order of the District Court insofar as it appears to dismiss Caldwell's complaint with prejudice. A dismissal with prejudice ordinarily operates as an adjudication on the merits; thus, Caldwell contends the District Court's dismissal in this case may effectively bar the relitigation of his claims. See Huffman v. Pursue, Ltd., supra, 420 U.S. at 606 n.18, 95 S. Ct. 1200. Since such a result is incompatible with the purposes of the Younger abstention doctrine, See Sartin v. Commissioner of Pub. Saf. of St. of Minn., supra at 433 n.5, the District Court's order is modified to provide that Caldwell's complaint is dismissed without prejudice.

Since we hold that Younger requires the dismissal of Caldwell's complaint, we need not reach the alternate grounds for dismissal which were cited by the District Court. Indeed, since dismissal of Caldwell's suit on abstention grounds terminated federal jurisdiction, the District Court's consideration of the alternate grounds for dismissal was of no effect since no case or controversy was then pending before the court. See First American Bank & Trust Company v. Ellwein, 474 F.2d 933 (8th Cir. 1973); Martin v. Merola, supra at 194.

In summary, we affirm the order of the District Court insofar as it dismisses Caldwell's action on the ground that federal restraint is required by the Younger abstention doctrine. That dismissal is modified, however, to be without prejudice. The remainder of the District Court's order, which cites alternative grounds for the dismissal of Caldwell's claims, is hereby vacated.

Affirmed in part, reversed in part, and vacated in part.