OPINION OF THE COURT
ADAMS, Circuit Judge.
The petition for mandamus presently before the Court presents two issues: the scope of this Court’s mandamus jurisdiction, and the power of the District Court of the Virgin Islands to summon an investigative grand jury.
I.
On April 28, 1980, the Assistant Attorney General of the United States requested the District Court of the Virgin Islands to convene a grand jury to investigate possible violations of the federal antitrust laws in the importing, wholesaling, and retailing of liquor in the Virgin Islands. The United States urged that the court’s authority to convene the grand jury derived either from Rule 6(a) of the Federal Rules of Criminal Procedure or from 18 U.S.C. § 3331(a). The district court, reasoning that it lacked the requisite authority, entered an order on December 12, 1980, denying the request. The government subsequently filed this petition for mandamus, asking that we direct the district court to summon a grand jury to investigate alleged violations of the federal antitrust laws. At the time of filing the mandamus petition, the government indicated that it intended to rely on 18 U.S.C. § 3331 as well as Rule 6(a) to support its position. See Petition for Writ at 2. The respondent continued to challenge 18 U.S.C. § 3331 as a source of authority for convening a grand jury. However, in a subsequent answering brief the United States stated that it sought review only of the refusal to summon a grand jury under Rule 6(a). See Answering Brief at 2 n.l.
II.
At the outset, we confront a potential barrier to our adjudication of this dispute. Because the government seeks a writ of mandamus, we initially must consider whether the prerequisites to entertaining the petition are satisfied.
Traditionally, federal appellate courts have issued the writ of mandamus where a lower court has made an error of “jurisdictional” dimension. Thus, the Supreme Court in Roche v. Evaporated Milk Association, 319 U.S. 21, 26, 63 S.Ct. 938, 941, 87 L.Ed. 1185 (1943), identified mandamus as the means “to confine an inferior court to a lawful exercise of its prescribed jurisdiction or to compel it to exercise its authority when it is its duty to do so.” 1 Jurisdiction in this sense, however, has been read broadly.2 In a variety of contexts, appellate courts have resorted to mandamus where the district court, in a case properly before it, took some action it was not empowered [894]*894to take3 or declined to take some action required of it.4
The present controversy, on superficial consideration, appears to present the paradigmatic case for mandamus review. The government contends that the district court, in declining to convene a grand jury, has failed to exercise an authority it was obliged to consider. The writ of mandamus, it is argued, provides the appropriate vehicle by which to remedy this failure to comply with applicable law. The unusual posture of the case, however, engenders special problems respecting the availability of mandamus relief. The principle of Mar-bury v. Madison, 5 U.S. (1 Cranch) 137, 2 L.Ed. 60 (1803) — that the Supreme Court has no original jurisdiction to issue the writ of mandamus — historically has applied as well to lower federal courts. Although there appears to be no constitutional impediment, the First Judiciary Act confined the lower courts to issuing writs in aid of an otherwise existing jurisdiction. See McIntire v. Wood, 11 U.S. (7 Cranch) 504, 3 L.Ed. 420 (1813).5 The current authorization for mandamus, embodied in the All Writs Act, 28 U.S.C. § 1651(a), preserves this restraint. It provides: “The Supreme Court and all courts established by Act of Congress may issue all writs necessary or appropriate in aid of their respective jurisdictions and agreeable to the usages and principles of law.”
To satisfy the jurisdictional prerequisite, it is not necessary that a case be pending in the court asked to issue the writ. See, e. g., United States v. Mellon Bank, N. A., 545 F.2d 869, 872 (3d Cir. 1976). Rather, it suffices that the case may at some future time come within the court’s appellate jurisdiction. As we explained in United States v. RMI Co., 599 F.2d 1183, 1186 (3d Cir. 1979), “the action must .. . involve subject matter to which our appellate jurisdiction could in some manner, at sometime, attach.”6 Before entertaining the application, then, we must identify a jurisdiction that the issuance of the writ might assist.
Because the district court has so far declined to convene a grand jury, there is currently pending no lawsuit that might eventually come before us on appeal. Indeed, one of the government’s arguments for issuance of the writ is that, absent mandamus, the district court’s decision will forever be shielded from review. It is, of [895]*895course, possible that some action not yet commenced may raise the issue the government would have us consider now.7 But prediction of future lawsuits is nothing more than speculation, and, in any event, the connection between such suits and the present petition is so attenuated that it cannot establish that issuance of the writ at this time woüld be “in aid of” our jurisdiction.
Although the requested writ cannot be issued pursuant to our eventual jurisdiction over any identifiable case, we are not persuaded that such jurisdiction is invariably a prerequisite to a grant of mandamus relief. This Court has previously made use of the writ of mandamus notwithstanding the lack of a specific controversy over which we might later exercise jurisdiction. In United States v. Malmin, 272 F. 785 (3d Cir. 1921), the Governor of the Virgin Islands, without authority, had revoked the appointment of district judge Malmin and replaced him with another judge. Because questions of the validity of the judgments of the functioning judge would arise “in a way which would leave this court helpless to correct the fundamental trouble” and insofar as it was “essential to the appellate jurisdiction of this court that orderly proceedings in the district court ... be restored,” the Court issued a writ ordering Malmin to reassume his duties as judge. Id. at 792. Indeed, eases in which, absent resort to mandamus, we would lose our ability to review the issue at all, present a wholly consistent example of mandamus as necessary for the exercise'of our jurisdiction. As described by adherents of a carefully circumscribed mandamus power: “The focal question posed for a Court of Appeals by a petition for the issuance of a writ is whether the action of the District Court tends to frustrate or impede the ultimate exercise by the Court of Appeals of its appellate jurisdiction granted in some other provision of the law.” LaBuy v. Howes Leather Co., 352 U.S. 249, 264, 77 S.Ct. 309, 317, 1 L.Ed.2d 290 (1957) (Brennan, J., dissenting).8 Here, the refusal of the district court to convene a grand jury to investigate antitrust violations may arguably impede the prosecution of crimes over which we would otherwise have review.
On at least three occasions, the Supreme Court, acting pursuant to Section 1651 or its predecessors, has granted the writ even though no controversy which subsequently could have been presented to the Court for review on the merits was then pending. In Ex parte Bradstreet, 32 U.S. (7 Pet.) 634, 8 L.Ed. 810 (1833), the district court had dismissed an action in which plaintiff had demanded the return of property, on the ground that the plaintiff had not averred the pecuniary value of the land, and therefore failed to satisfy the $2,000 amount-in-controversy requirement. Because the action had already been dismissed, and there was accordingly no pending federal action, plaintiff’s petition to the Supreme Court for a writ of mandamus did not fall within the tribunal’s “potential” jurisdiction over a specific controversy. Nonetheless the Court, in a brief opinion by Chief Justice Marshall, issued the writ, directing the district court to reinstate the case. Id. at 649, 8 L.Ed. 810.
Ex parte United States, 287 U.S. 241, 53 S.Ct. 129, 77 L.Ed. 283 (1932), similarly involved a situation where, at the time the Supreme Court considered the request for mandamus, there was no pending action over which the Court’s jurisdiction might [896]*896some day attach. In that case a United States Attorney, having secured a grand jury indictment against Joseph Wingert, petitioned the district court to issue a bench warrant for Wingert’s arrest. When the court refused, the government, by-passing the court of appeals, petitioned the Supreme Court for a writ of mandamus directing the district judge to issue the warrant. In granting the writ, the only jurisdictional question that detained the court was whether it could issue the writ notwithstanding the fact that direct review from district court decisions is vested in the courts of appeals, rather than the Supreme Court. The Court was not troubled by the absence of a pending lawsuit; indeed, the premise of the Court’s discussion was that the court of appeals had authority to issue the writ, see id. at 249, 53 S.Ct. at 131, even though, as the district court’s opinion indicates, see 55 F.2d 960, 963 (E.D.Pa.1932), mandamus supplied the only basis for appellate review.
More recently, in Thermtron Products, Inc. v. Hermansdorfer, 423 U.S. 336, 96 S.Ct. 584, 46 L.Ed.2d 542 (1976), the Supreme Court considered the appropriateness of using mandamus to require a district court to entertain a diversity action it had improperly remanded to state court. The Court, without mention of whether the writ would aid appellate jurisdiction when there was no longer a live federal case, granted the requested relief. Mandamus, it said, would help “prevent nullification of the removal statutes by remand orders resting on grounds having no warrant in the law." Id. at 353, 96 S.Ct. at 594.
Ex parte Bradstreet, Ex parte United States, and Thermatron Products jointly suggest that a controversy may fall within the “potential jurisdiction” of an appellate tribunal for purposes of Section 1651, even absent a pending federal action that might ultimately be appealed. Ex parte United States, moreover, indicates that the jurisdictional prerequisite may be satisfied even though no such action was ever pending in federal court. These three cases should not be read too generously, however, and we do not interpret them to sanction a broad supervisory authority over the lower courts. Instead, we regard the precedents as establishing a principle of limited application: where a district court, by action not committed to its discretion, prevents a nascent controversy from being adjudicated and thereby defeats appellate review, the subject matter of the court’s action is within the “jurisdiction” of the appellate court for purposes of the All Writs Act.
Applied to the present case, these principles support our power to entertain the government’s petition. The government alleges that the district court, in declining even to consider whether to summon a grand jury, has breached a duty that is not committed to its discretion. Further, the purported consequence of this decision is that the United States will be precluded from adequate investigation and prosecution of criminal activity, thereby barring the emergence of controversies cognizable in federal court. Although the district court’s action will not interfere with our review of any case currently pending in the federal system, we believe that the present dispute, affects our “jurisdiction” as that term is used in Section 1651.
Various of the Supreme Court’s recent illuminations of the scope and purpose of the mandamus remedy strengthen this conclusion. Tn LaBuy v. Howes Leather Co., 352 U.S. 249, 77 S.Ct. 309, 1 L.Ed.2d 290 (1957), the Court employed the writ to compel a district court to vacate orders referring an antitrust case for trial before a master. The Court in so doing suggested that mandamus might be used “as a means of policing compliance with the procedural rules,” see Will v. United States, 389 U.S. 90, 100 n.10, 88 S.Ct. 269, 276, n.10, 19 L.Ed.2d 305 (1967), by using it to review orders that are part of a general practice adopted by the district court which is outside the scope of the rules. While review of individual discretionary decisions is improper, appellate tribunals should consider charges that a lower court’s approach to a rule effectively “nullifies” it. See 352 U.S. at 256-57, 77 S.Ct. at 313-14. The present [897]*897case involves such a systemic problem. The district judge simply does not believe he possesses the power to summon a grand jury, while the government adopts a contrary construction of the rules and statutes. The issue of discretionary authority is not presented, for the parties agree that the district court’s power was either granted or forbidden. The case at hand thus presents an opportunity for mandamus review to fulfill its “vital corrective and didactic function.” Will, 389 U.S. at 107, 88 S.Ct. at 279.
The Supreme Court stressed the pedagogic value of the writ in Schlagenhauf v. Holder, 379 U.S. 104, 110, 85 S.Ct. 234, 238, 13 L.Ed.2d 152 (1964). There it approved mandamus review to decide the “basic, undecided” question whether a district court could order the mental or physical examination of a defendant pursuant to Rule 35(a) of the Federal Rules of Civil Procedure. Similarly, the question presented here is one of first impression, and review would comport with the instructional goals of mandamus. Consideration of the petition also serves the policy of limiting the writ to extraordinary circumstances by insisting “that the party seeking issuance of the writ have no other adequate means to attain the relief he desires.” Kerr v. United States District Court, 426 U.S. 394, 403, 96 S.Ct. 2119, 2124, 48 L.Ed.2d 725 (1976); First Jersey Securities, Inc. v. Bergen, 605 F.2d 690, 701 (3d Cir. 1979). As explained above, the district court, should it persist in its interpretation of the law, will foreclose the opportunity for testing its construction on direct appeal. Review through a petition for mandamus thus appears to be the only practical way to resolve this unsettled and important question.
We note finally that the policies that typically militate against consideration of a petition for mandamus are inapposite here. The case does not implicate the general policy against piecemeal appeals, see First Jersey, 605 F.2d at 702, inasmuch as there is as yet no ongoing action that review would disrupt. Moreover, although the cases arise in the context of the federal criminal statutes and procedural rules, review will not endanger the right of an individual criminal defendant to a speedy trial. United States v. Marion, 404 U.S. 307, 92 S.Ct. 455, 30 L.Ed.2d 468 (1971) (Sixth Amendment’s speedy trial guarantee applies to period between indictment and trial); Will v. United States, 389 U.S. at 96, 88 S.Ct. at 274.
In view of such considerations, we proceed to consider the merits of the petition.
III.
The grand jury as an institution was adopted from the common law and, secured in the Fifth Amendment, became a fundamental part of our country’s system for the prosecution of crime. See Ex parte Bain, 121 U.S. 1, 6, 7 S.Ct. 781, 784, 30 L.Ed. 849 (1887); United States v. Calandra, 414 U.S. 338, 343-44, 94 S.Ct. 613, 617-18', 38 L.Ed.2d 561 (1974). While neither the Constitution nor statutory law originally defined the scope of grand jury functions, it was established early on by the judiciary that the authority to summon grand juries was a corollary of the criminal jurisdiction of the federal courts. As Chief Justice Marshall explained:
It has been justly observed, that no act of Congress directs grand juries, or defines their powers. By what authority, then, are they summoned, and whence do they derive their powers? The answer is, that the laws of the United States have erected courts which are invested with criminal jurisdiction. This jurisdiction they are bound to exercise, and it can only be exercised through the instrumentality of grand juries. They are, therefore, given by a necessary and indispensable implication. But, how far is this implication necessary and indispensable? The answer is obvious. Its necessity is co-extensive with that jurisdiction to which it is essential.
United States v. Hill, 1 Brock 156, 159, 26 Fed.Cas. 315, 317 (C.C.D.Va.1809). Because the Fifth Amendment guarantees that “no person shall be held to answer for a capital, or otherwise infamous crime, unless on a presentment or indictment of a grand jury,” federal courts possess inherent power [898]*898to convene grand juries when they are necessary to satisfy the constitutional mandate.
Absent such a necessary implication from the Constitution, however, there is some question whether courts .have inherent power to convene grand juries. In discussing the authority of a territorial court, the elder Justice Harlan remarked:
A grand jury, by which presentments or indictments may be made for offences against the United States, is a creature of statute. It cannot be empanelled by a court of the United States by virtue simply of its organization as a judicial tribunal.
In Re Mills, 135 U.S. 263, 267, 10 S.Ct. 762, 763, 34 L.Ed. 107 (1890). And more recently, the Second Circuit, in United States v. Fein, 504 F.2d 1170, 1172 (2d Cir. 1974), declared that grand juries are not “creatures of the court”; rather, the power of courts over grand juries is guided by rules and statutes.9 The Fein court sought to reconcile the language in Hill and Mills by noting that Chief Justice Marshall’s opinion was written in 1809, “long before Congress had enacted any legislation regulating the powers or the tenure of grand juries.” 504 F.2d at 1172. In Mills the issue was the power of an Article I territorial court, whereas in Hill the discussion centered on Article III courts.
In canvassing the possible sources that might confer power on the District Court of the Virgin Islands to summon a grand jury, we are limited. It would appear that power cannot derive simply from the court’s inherent supervisory authority over activities within its purview. Nor is it clearly implied by necessity from the Fifth Amendment’s command, for it was settled at the time our nation began acquiring territories that, at least with respect to prosecutions under local law, specific protections and rights conferred by the Constitution do not apply “to territory belonging to the United States which has not been incorporated into the Union.” Balzac v. Porto Rico, 258 U.S. 298, 305, 42 S.Ct. 343, 345, 66 L.Ed. 627 (1922); Dorr v. United States, 195 U.S. 138, 145, 24 S.Ct. 808, 811, 49 L.Ed. 128 (1904). Therefore, this Court, following the directions provided in Balzac v. Porto Rico, 258 U.S. 298, 42 S.Ct. 343, 66 L.Ed. 627 (1922); Dorr v. United States, 195 U.S. 138, 24 S.Ct. 808, 49 L.Ed. 128 (1904) and Hawaii v. Mankichi, 190 U.S. 197, 23 S.Ct. 787, 47 L.Ed. 1016 (1903), has held that the Fifth Amendment’s grand jury protection does not extend to prosecutions initiated in the Virgin Islands.
In all the cases holding that constitutional projections relating to the conduct of criminal prosecutions do not apply in the absence of statute to unincorporated territories, the Supreme Court reasoned that the United States, in acquiring such possessions, did not intend to supplant indigenous procedural rules which had developed to enforce local substantive norms.10 It might be ar[899]*899gued that the existence of a territorial tradition unlike our own should not defeat application of constitutional guarantees when the United States, rather than the territorial government, seeks to investigate and prosecute violations of federal, rather than local, law. However, in light of this Court’s decision in Government of Virgin Islands v. Dowling, 633 F.2d 660 (3d Cir. 1980), which held that the Fifth Amendment requirement of a grand jury does not apply in the Virgin Islands even for a prosecution under federal law, we find no constitutional basis for investigatory grand juries in the territory.
Even if the Constitution does not apply,11 however, the Virgin Islands, as an unincorporated territory, 48 U.S.C. § 1541(a), is governed by a congressionally enacted Bill of Rights. 48 U.S.C. § 1561. We have previously held that such Bill of Rights “expresses the congressional intention to make the federal constitution applicable to the Virgin Islands to the fullest extent possible consistent with its status as a territory.” In Re Brown, 439 F.2d 47, 51 (3d Cir. 1971) (en banc). The Virgin Islands Bill of Rights extends the Fifth Amendment to that territory, but also states “[t]hat all offenses shall continue to be prosecuted in the district court by information as heretobefore, except such as may be required by local law to be prosecuted by indictment by grand jury.” 48 U.S.C. § 1561. Therefore neither constitutional nor organic statutory provisions can readily be construed to authorize, even by implication, the Virgin Islands District Court to convene a grand jury. See Government of Virgin Islands v. Rijos, 285 F.Supp. 126, 129 (D.V.I.1968).
Nevertheless, since Chief Justice Marshall’s time Congress has enacted several statutes explicitly providing for grand juries. In the present proceeding the government originally suggested two sources for the judicial power to summon a grand jury: Rule 6(a) of the Federal Rules of Criminal Procedure, and 18 U.S.C. § 3331(a), which permits the creation of special grand juries “because of criminal activity in the district.” Judge Christian, however, expressed the concern that the Virgin Islands District Court’s authority in the criminal field is not congruent with that of other federal trial courts. In his view, the Virgin Islands tribunal does not share the power to summon a grand jury for indictment or investigative purposes. The government, after certifying to the district court in accordance with Section 3331 the need for a special grand jury, has sought mandamus only with respect to the district court’s refusal to convene a jury pursuant to Fed.R.Crim.P. 6(a).12 In view of this decision by the government, we turn to Rule 6(a).
IV.
As authorized by Congress, the District Court of the Virgin Islands possesses a hybrid jurisdiction that combines the powers of a federal court with those ordinarily reserved for state tribunals. The court possesses both “the jurisdiction of a district court of the United States” over cases arising under the federal constitution and laws, and “general original jurisdiction” in all other causes. 48 U.S.C. § 1612. The Federal Rules of Criminal Procedure govern in the District Court of the Virgin Islands pursuant to Rule 54(a). Those Rules have the force of statute,13 and thus might, as [900]*900the government maintains, provide an appropriate source of authority for the District- Court to convene a grand jury.
Rule 6(a) reads:
Summoning Grand Juries. The court shall order one or more grand juries to be summoned at such times as the public interest requires. The grand jury shall consist of not less than 16 nor more than 23 members. The court shall direct that a sufficient number of legally qualified persons be summoned to meet this requirement.
If this Rule applied with full force in the Virgin Islands, it arguably would confer on the district court the authority to convene a grand jury to investigate crimes and indict where it found probable cause. See, e. g., United States v. Wallace & Tiernan, Inc., 349 F.2d 222, 226 (D.C.Cir.1975). The investigatory powers of such a grand jury would be broad, since the federal system allows grand juries wide compass in their inquiries. See, e. g., United States v. Calandra, 414 U.S. 338, 343, 94 .S.Ct. 613, 617, 38 L.Ed.2d 561 (1974). In the Virgin Islands, however, the authority provided by Rule 6(a) is circumscribed. Rule 54(a), which extends the application of the Rules to the Virgin Islands, carves out a significant exception: “all offenses shall continue to be prosecuted in ... the District Court of the Virgin Islands by information as heretofore except such as may be required by local law to be prosecuted by indictment by grand jury.” This exception reflects and incorporates the substance of Section 25 of the Revised Organic Act of the Virgin Islands, 48 U.S.C. § 1615, which provides for prosecution by information rather than indictment unless otherwise required by local law. In light of Rule 54(a) and Section 25, Rule 6(a) cannot be read to authorize indicting grand juries in the Virgin Islands. The government suggests that Rule 6(a) can nevertheless provide authority for grand juries in the Virgin Islands that investigate but do not indict. Although 54(a) does not specifically forbid such grand juries, we find nothing in Rule 6(a) which can fairly be construed to authorize them.
Many states that prosecute by information still provide for investigatory grand juries, especially when large and intricate conspiracies or public corruption are at stake. For example, Pennsylvania, which previously authorized such juries under common law, see Note, Discretionary Power in the Judiciary to Organize a Special Investigating Grand Jury, 111 U.Pa.L.Rev. 954 (1963), has recently spelled out by legislation the powers it considers appropriate for its “investigating grand juries.” 42 Pa. Cons.Stat.Ann. §§ 4541 — 4553 (Purdon 1981). That law empowers investigatory grand juries to subpoena witnesses and inquire into criminal offenses within the Commonwealth, initiate civil and criminal contempt proceedings, and issue presentments against any person within its jurisdiction who appears to have committed an offense against the Commonwealth. 42 Pa.Cons.Stat.Ann. § 4548. We presume that the government in this case seeks to have the District Court of the Virgin Islands authorize a similar type of institution — in effect, a body with all the powers of a normal grand jury short of the power to indict. However, we are unable to find in the Federal Rules any language that would create such an entity in the way that Pennsylvania’s common law and statutory provisions do.
The federal courts have long recognized the vital investigatory function which grand juries perform in the federal system. See, e. g., Branzburg v. Hayes, 408 U.S. 665, 701, 92 S.Ct. 2646, 2666, 33 L.Ed.2d 626 (1972); Blair v. United States, 250 U.S. 273, 282, 39 S.Ct.'468, 471, 63 L.Ed. 979 (1919); Hale v. Henkel, 201 U.S. 43, 65, 26 S.Ct. 370, 375, 50 L.Ed. 652 (1906). Indeed, some commentators have suggested that the grand [901]*901jury’s role as investigator is at least as important a contribution to our legal system as is its role as protector of individual rights. See Note, Investigating Grand Juries: A Comparison of Pennsylvania’s Judicially and Legislatively Created Bodies, 18 Duq.L.Rev. 933, 933 (1980). But no authority advocates investigation for its own sake; the grand jury’s inquisition must culminate in a disposition that furthers the prosecutorial process. Although it may ultimately fail to uncover any crime, a federal grand jury’s investigation can still be justified by the possibility that it might have resulted in the issuance of criminal charges. As the Supreme Court explained in Blair, in describing the grand jury’s powers:
It is a grand inquest, a body with powers of investigation, the scope of whose inquiries is not to be limited narrowly by questions of propriety or forecasts of the probable result of the investigation, or by doubts whether any particular individual will be found properly subject to an accusation of a crime. As has been said before, the identity of the offender, and the precise nature of the offense, if there be one, normally are developed at the conclusion of the grand jury’s labors, not at the beginning.
250 U.S. at 282, 39 S.Ct. at 471; accord, Branzburg, supra, 408 U.S. at 688, 92 S.Ct. at 2660. See generally United States v. Cox, 342 F.2d 167, 185-96 (5th cir. 1975) (en banc) (Wisdom, J., concurring specially). By its own terms this recognition of investigatory powers cannot be read to extend to situations in which the grand jury lacks the power to make formal accusations. Rather, it ties the grand jury’s broad investigative power to its ultimate decision whether to accuse a suspect of a crime.
For the Virgin Islands, the Federal Rules withhold any means by which grand juries might make formal accusations. As noted above, Rule 54(a) specifically denies authorization for indictment except as required by the local legislature. Further, it appears, the Rules do not empower grand juries in the Virgin Islands or elsewhere to make “presentments” — reports of the grand jury to the court asking that a “charge be drawn to cover the facts should they constitute a crime,” United States v. Smyth, 104 F.Supp. 283, 295 (N.D.Cal.1952). As the Court of Appeals for the Fifth Circuit has noted, “the practice of using presentments has disappeared in the federal system and is not provided for in F.R.Crim.P. Rules 6 and 7.” United States v. Briggs, 514 F.2d 794, 803 n.14 (5th Cir. 1975). This reading of the Rules is strengthened by the Notes of the Advisory Committee to Rule 7, which provide that:
Presentment is not included as an additional type of formal accusation, since presentments as a method of instituting prosecutions are obsolete, at least as concerns the Federal courts.
It is conceivable, of course, that Congress would wish to preserve accusation by presentment where it is not obsolete, and the Virgin Islands might be considered such a place because indictment is not available. Though such a policy might be considered advisable, nothing in the language of Rules 6 and 7 lends any support to the proposition that any federal grand juries are authorized to make presentments.
Indeed, in light of Rule 54(a) and the parallel Section 25 of the Virgin Islands Organic Act it would be difficult to find authority for a grand jury to make presentments in the Virgin Islands even if federal grand juries elsewhere had such power. The legislative history of the 1954 amendments to Section 25 suggests two concerns: a reluctance to provide for a right to grand jury indictment — a right that might lead to a general jail delivery of the territory’s prisoners — and a desire to avoid creating a prosecuting body that would conflict with the Islands’ civil law heritage.14 In light of [902]*902the second concern it is difficult to conceive of a rationale that would motivate Congress to permit grand jury presentment but withhold authorization for indicting grand juries. If the latter would violate local traditions and customs, the former, differing only in that the grand jury would not formally institute proceedings but would recommend to the court that proceedings be instituted, would appear equally obtrusive. Presentment is no more familiar to Virgin Islands’ tradition than is indictment. In the absence of a clear expression permitting presentments in the Virgin Islands, we are unable to infer such an intent from either the Federal Rules or Section 25 of the Revised Organic Act.
If the government’s proposed investigatory grand jury may neither indict nor present, it can serve no effective accusatorial purpose. The only remaining possible function would be the issuance of reports of some sort. In a variety of circumstances federal grand juries have been permitted to issue reports in addition to or even in place of indictments. The only explicit statutory authority for such reports is contained in the provisions for special grand juries under 18 U.S.C. §§ 3331-3334.15 Although federal grand juries not convened pursuant to that statute may also have some reporting powers, see In re Report and Recommendations of June 5, 1972 Grand Jury Concerning Transmission of Evidence to the House of Representatives, 370 F.Supp. 1219, 1223-24 (D.D.C.1974),16 the government has cited no case in which a federal grand jury was convened with the sole power and purpose of issuing such reports.17 Such an institu[903]*903tion would be foreign to the federal judiciary as it now exists; even grand juries convened under Sections 3331-3334 retain the power to indict. See United States v. Ceccerelii, 350 F.Supp. 475 (W.D.Pa.1972). Whatever the merits of creating a non-indicting grand jury, we do not find in- the general language of Rule 6 any expression of an intent to authorize an unprecedented institution such as this.
V.
We recognize that an investigatory grand jury might serve a valuable function in the prosecutorial system of the Virgin Islands. In light of the serious crime problems existing in that and other jurisdictions, we are reluctant to deny the Islands the power to invoke an investigative device that elsewhere has served the legal system as a guardian of both social needs and individual rights.18 Nevertheless, we are constrained by the absence of authority to institute such grand juries in the Virgin Islands. Although the creation of an investigatory grand jury, or even an indicting grand jury, might be salutary, it is not for the courts to institute such an entity without legislative direction. We must, therefore, defer to the Virgin Islands’ legislature or the United States Congress to authorize for the Virgin Islands such grand juries as are deemed appropriate.
Accordingly, the petition for a writ of mandamus is denied.