Daniel ANDERSEN and Lorenzo J. Lamantia, individually and on behalf of the members of the Institute for Global Prosperity, Plaintiffs-Appellants, v. UNITED STATES of America, Named and Unnamed Agents of the Internal Revenue Service Criminal Division, IRS Special Agent Thomas Wourgiotis, IRS Special Agent Tom Oenbrink, IRS Special Agent Paula Lurvey, IRS Special Agent Jeffrey Holm, IRS Special Agent Julie Lau, IRS Special Agent Charles Phillips, IRS Special Agent Judy O'Briant and Shoshanna Szuch, Defendants-Appellees, 298 F.3d 804

Opinion by Judge Graber; Dissent by Judge Reinhardt. OPINION GRABER, Circuit Judge. Plaintiffs Andersen and LaMantia, on behalf of themselves and the members of the Institute for Global Prosperity (IGP), sued the United States and its agents. Plaintiffs alleged that the government .conspired to violate their constitutional rights and those of IGP’s members when the government executed eight search warrants and seized, among other things, IGP’s membership lists and literature.

Plaintiffs moved for an injunction (1) to prevent the government from conducting further searches or seeking further information, (2) to prevent the government from using the information obtained from search warrants already executed, and (3) to require the government to return the seized property. The district court denied the motion. We dismiss Plaintiffs’ appeal for lack of jurisdiction.

FACTS AND PROCEDURAL HISTORY Plaintiffs are leaders of IGP, an organization that distributes “educational, political, religious and philosophical materials in the form of books and CDs, much of which is critical of the United States’ financial and taxing policies.” Plaintiffs and other IGP leaders are currently under investigation for tax-related crimes. Between February 28, 2001, and September 25, 2001, the government executed eight search warrants on Plaintiffs’ residences and on IGP offices across the country. The warrants sought a broad range of financial records.

The warrants also sought material under the heading “[IGP] related records/ evidence,” including applications for membership, membership cards, membership agreements, confidentiality agreements, promotional literature (letters, flyers, brochures, videotapes and audiotapes), scripts used during telephone solicitations, newspaper advertisements, lists of names or addresses or telephone numbers (or other identifying data) of members, prospective members or Qualified Retailers, records reflecting attendance at [IGP] seminars, videotapes/audiotapes of [IGP] leaders/members at [IGP] seminars, and audiotapes of [IGP programs].

On September 28, 2001, Plaintiffs filed this action in federal district court, alleging claims of (1) conspiracy to violate Plaintiffs’ First and Fourth Amendment rights and the First Amendment rights of members and associates of IGP and (2) “willful, wanton and malicious violations” of Plaintiffs’ individual Fourth Amendment rights. At the same time, Plaintiffs filed a motion for a temporary restraining order and a preliminary injunction. They sought to prohibit the United States from (

a) conducting any further searches and seizures or otherwise seeking or acquiring indicia of association with plaintiffs and/or IGP’s members and/or associates; and (

b) any use or dissemination to any person, entity or agency whatsoever of any membership and/or associates’ identities or information already obtained during the searches and seizures at issue Plaintiffs also sought a permanent injunction ordering the return of all IGP-related property that had been seized pursuant to the warrants. The district court denied the request for a temporary restraining order and, later, denied Plaintiffs’ motion for a preliminary injunction. Plaintiffs timely filed a notice of appeal.

DISCUSSION As a threshold matter, we must decide whether we have jurisdiction to review the district court’s denial of the preliminary injunction. Generally, we may review only final orders of the district court. 28 U.S.C. § 1291. [1] The denial of a preliminary injunction is one of the few kinds of ap-pealable interlocutory orders. 28 U.S.C. § 1292(a)(1). However, here, Plaintiffs’ motion sought relief typically provided by Federal Rule of Criminal Procedure 41(e).

Although styled as an action for an “injunction,” perhaps because of the general rule noted above, the motion in substance sought the return of property that had been seized pursuant to a warrant. Rule 41(

e) controls the procedure for obtaining that form of relief. The distinction between injunction proceedings in general and Rule 41(

e) motions in particular is important, because the denial of a motion under Rule 41(

e) usually is not appealable. DiBella v. United States, 369 U.S. 121, 131-32, 82 S.Ct. 654, 7 L.Ed.2d 614 (1962). The substance of the motion, not its form, controls its disposition. See Prudential Real Estate Affiliates, Inc. v. PPR Realty, Inc., 204 F.3d 867, 880 (9th Cir.2000) (“[T]he label attached to a motion does not control its substance.” (citation and internal quotation marks omitted)); Hasbrouck v. Texaco, Inc., 879 F.2d 632, 635 (9th Cir.1989) (“The nomenclature the movant uses is not controlling.

This court must decide whether a motion, however styled, is appropriate for the relief requested.” (citations omitted)). In accordance with that principle favoring substance over form, we have construed a motion that sought injunctive relief of the kind provided by Rule 41(

e) as a Rule 41(

e) motion, notwithstanding the motion’s label. See, e.g., DeMassa v. Nunez, 747 F.2d 1283, 1291 (9th Cir.1984) (Ferguson, J., dissenting), reh’g granted on other grounds, 770 F.2d 1505 (9th Cir.1985) (per curiam) (DeMassa I and DeMassa II, respectively). Because Plaintiffs sought the relief provided by Rule 41(e), we construe their motion as one properly brought under that rule. The Supreme Court has held that the courts of appeal have jurisdiction to review decisions on Rule 41(

e) motions “[o]nly if the motion is solely for return of property and is in no way tied to a criminal prosecution in esse against the movant.” DiBella, 369 U.S. at 131-32, 82 S.Ct. 654. As we recently recognized: This rule reflects the careful balancing between two competing interests: On the one hand, appellate courts should act to prevent the deprivation of seized property that is sorely needed when those deprived have no other avenues for relief.

On the other hand, the appeal of a lower court’s decision denying a return of property can add uncertainty and delay to an ongoing parallel criminal proceeding, especially if the legality of the search is the critical issue in the criminal trial. Bridges v. United States (In re 3021 6th Ave. N.), 237 F.3d 1039, 1041 (9th Cir. 2001). In this case, Plaintiffs’ motion seeks the return of the seized property but also asks for significant additional relief. And, there is an ongoing criminal investigation that targets Plaintiffs.

In the circumstances, Plaintiffs fail both parts of DiBella’s test, and they therefore cannot establish the exception to the general rule that motions like theirs are unappealable. As for the first criterion, in addition to demanding the return of their property, Plaintiffs seek to enjoin the IRS from conducting any future searches or seizures. Further, they seek to enjoin the IRS from using the material that already was seized.

By asking for exclusion of evidence and by seeking to prevent any further searches, the complaint seeks relief beyond “solely” the return of property. [5] As for the second criterion, an ongoing grand jury investigation constitutes a “ ‘criminal prosecution in esse’” under DiBella. DeMassa I, 14R F.2d at 1291 (Ferguson, J., dissenting) (quoting DiBella, 369 U.S. at 132, 82 S.Ct. 654). In this circuit, rulings on motions for return of property are unappealable when there is an ongoing grand jury investigation. Id. Indeed, DeMassa I directly controls this case.

In DeMassa I, we construed a motion for a preliminary injunction as a Rule 41(

e) motion. Because one of the plaintiffs was the target of an ongoing grand jury investigation, we held that we lacked jurisdiction to review the order denying injunc-tive relief. See id. at 1287 (stating that “[tjhis circuit has joined those courts adopting a liberal definition of when a proceeding is in esse and has also concluded that an order denying the return of seized property is not appealable when a grand jury proceeding against the movant is underway”). DeMassa I clearly contemplates that grand jury proceedings constitute criminal proceedings for the purpose of determining appealability. This

interpretation is consistent with DiBella, which held that “the mere circumstance of a pre-indictment motion does not transmute the ensuing evidentiary ruling into an independent proceeding begetting finality even for purposes of appealability. Presentations before a ... grand jury are parts of the federal prosecutorial system leading to a criminal trial.” DiBella, 369 U.S. at 131, 82 S.Ct. 654 (citations omitted) (emphasis added). Plaintiffs ask for an exception to the rule of nonappealability on the ground that their First Amendment rights allegedly have been infringed.

Although DiBella and DeMassa dealt with Fourth Amendment rights, the broad proscription against interlocutory review that those cases establish applies with equal force to First Amendment claims. We recognize that First Amendment rights may be chilled when the government seizes information about the members of an organization. NAACP v. Alabama, 357 U.S. 449, 462-68, 78 S.Ct. 1163, 2 L.Ed.2d 1488 (1958). Nonetheless, for three reasons, we conclude that the Supreme Court would apply the DiBella rule even to a First Amendment claim. First, the Court’s logic in DiBella retains its efficacy in this context.

The Court gave two reasons for refusing to create an exception to the general finality rule: The Court was concerned with impeding the criminal justice process, including the Sixth Amendment right to a speedy trial, 369 U.S. at 124, 126, 82 S.Ct. 654, and it concluded that Rule 41(

e) motions are not independent of the associated criminal investigation and thus not severa-ble from the “larger litigious process,” id. at 127, 82 S.Ct. 654 (citation and internal quotation marks omitted). In other words, permitting an appeal from the district court’s decision on a Rule 41(

e) motion is likely to affect the integrity of the investigation and potential criminal trial. Id. These concerns are equally valid whatever the specific nature of the constitutional right that the potential criminal defendant seeks to vindicate. Second, the bar against an interlocutory appeal means only that review on the merits is postponed, not foreclosed. Plaintiffs can obtain appellate review on the merits of their claims when the district court has taken final action, either in the context of a criminal conviction or otherwise.

Third, we note by way of analogy the Supreme Court’s application of a procedural bar even in the face of substantial First Amendment claims. In United States v. American Friends Service Committee, 419 U.S. 7, 95 S.Ct. 13, 42 L.Ed.2d 7 (1974) (per curiam), the Supreme Court reversed an injunction that had been granted on First Amendment grounds. Employees of the American Friends Service Committee, who were Quakers, obtained an injunction that prevented the government from enforcing mandatory tax-withholding requirements. Id. at 9, 95 S.Ct. 13. Because of their religious objection to the war in.

Vietnam, the employees contended that the Free Exercise Clause protected their right to express those beliefs by refusing to pay a portion of their taxes. Id. at 7-8, 95 S.Ct. 13. Despite the strong First Amendment interests at stake, the Court imposed a statutory bar against equitable relief. Construing the Anti-Injunction Act, 26 U.S.C. § 7421(a), the Court reaffirmed the principle that “the constitutional nature of a taxpayer’s claim” under the First Amendment was irrelevant to its analysis. Am. Friends, 419 U.S. at 11, 95 S.Ct. 13 (citation and internal quotation marks omitted).

We express no opinion on whether the Anti-Injunction Act would bar Plaintiffs’ suit on the merits; it is not clear whether it would or would not. See Church of Scientology v. United States, 920 F.2d 1481, 1486 (9th Cir.1990) (noting that the Act extends to suits that target any activity that is “ ‘intended to or may culminate in the assessment or collection of taxes’ ” (quoting Blech v. United States, 595 F.2d 462, 466 (9th Cir.1979))).

However, analogizing from American Friends, we conclude that no exception to the procedural bar may be made here on the ground that Plaintiffs assert First Amendment as well as Fourth Amendment interests. Although the dissent emphasizes the compelling nature of First Amendment claims, our jurisdiction is bounded by the clear rule in DiBella, as interpreted by this court in DeMassa. We are not free to ignore those precedents defining our jurisdiction simply because the subject matter of the underlying complaint tempts us to do so.

That is true even in the Younger abstention context, on which the dissent relies by analogy. See Younger v. Harris, 401 U.S. 37, 91 S.Ct. 746, 27 L.Ed.2d 669 (1971) (limiting Dombrowski v. Pfister, 380 U.S. 479, 85 S.Ct. 1116, 14 L.Ed.2d 22 (1965), to its facts and abstaining despite an underlying First Amendment claim). CONCLUSION Plaintiffs’ motion for a preliminary injunction was, in substance, a motion for return of property under Federal Rule of Criminal Procedure 41(e), but it sought additional relief and was tied to an ongoing grand jury investigation.

Therefore, the district court’s order denying the injunction is not a final, appealable order, and we lack jurisdiction to review it. APPEAL DISMISSED. . At oral argument, the parties agreed that we should assume for the purpose of decision that there is a grand jury investigation in progress. Although the government makes no factual representations on this issue, we so assume. See Fed.R.Crim.P. 6(e) (providing for secrecy of grand jury proceedings). . For jurisdictional purposes, we are obliged to determine the finality of a decision on appeal. Regula v.

Delta Family-Care Disability Survivorship Plan, 266 F.3d 1130, 1136-37 (9th Cir.2001). We review de novo questions of our jurisdiction. Didrickson v. United States Dep't of Interior, 982 F.2d 1332, 1337 (9th Cir.1992). . The dissent relies on two brief passages in DiBella, 369 U.S. at 124-26, 82 S.Ct 654, to argue that it ”do[es] not set forth an absolute rule prohibiting all interlocutory appeals in cases involving criminal proceedings.” Dissent at 812. In the cited passages, however, the DiBella Court was merely describing, as background, extant exceptions to the finality rule, none of which applies here.

The Court went on to state the applicable and clear two-part test that we summarize in the text above. 369 U.S. at 131-32, 82 S.Ct. 654. . In DeMassa I, we held that we lacked jurisdiction to review the Fourth Amendment claims of a lawyer whose offices had been searched and whose files had been seized. Because that lawyer was the target of an ongoing grand jury investigation, we concluded that DiBella controlled, and we had no jurisdiction. 747 F.2d at 1287.

However, in DeMassa II, we held that we did have jurisdiction to review the Fourth Amendment claims of the clients who were also individually named plaintiffs. 770 F.2d at 1506. We reasoned that those clients were "strangers to any potential indictments” and, thus, their claims were reviewable under DiBella be-caúse there was no criminal proceeding in esse. Id. The clients in DeMassa II were named plaintiffs in the action. By contrast, the IGP is not a plaintiff, nor are any individual members named as plaintiffs except Andersen and LaMantia.

Andersen and LaMantia purportedly assert rights on the membership’s behalf. Without jurisdiction over any of Andersen’s or LaMantia’s claims, however, we cannot assert jurisdiction over the membership's potential derivative claims, even if Andersen and La-Mantia otherwise would be entitled to bring such claims in a representative capacity. .

Subject to certain statutory exceptions not applicable here, the Anti-Injunction Act provides that "no suit for the purpose of restraining the assessment or collection of any tax shall be maintained in any court by any person, whether or not such person is the person against whom such tax was assessed." 26 U.S.C. § 7421(a).