Opinion for the Court filed by Circuit Judge SENTELLE.
Dissenting opinion filed by Circuit Judge SILBERMAN.
SENTELLE, Circuit Judge:
William J. Kilroy appeals from a criminal judgment entered upon his conditional plea of guilty in which he preserved, inter alia, the issue of whether the indictment against him had been obtained in violation of immunity promised him in a plea agreement in a prior case. He raises only that issue on appeal. As we agree with the district court that the government has met its burden of establishing that its prosecution was untainted by improper use of immunized statements, we affirm.
I. The Facts
Between 1981 and 1985, an organized crime task force of the Department of Justice investigated Kilroy, an insurance broker, on suspicion that he (and others) had sold fraudulent insurance coverage to a union pension fund in Las Vegas. ' In June, August and November of 1983, FBI agents and investigators from the Department of Labor interviewed Kilroy, who proved cooperative by disclosing relevant facts and documents. On March 26,1985, a Las Vegas grand jury that had heard a synopsis of Kilroy’s 1988 statements returned an indictment against him and others charging offenses arising out of the sale of fiduciary liability insurance to a culinary union through a sham company.
Kilroy then acquiesced to further interrogation by FBI agents; on August 1 and 2, 1985, Kilroy informed them that he had embezzled pension funds held in trust for the National Council of Senior Citizens (NCSC), a nonprofit corporation located in the District [682]*682of Columbia. On August 14, Kilroy agreed to plead guilty to one count of the Las Vegas indictment and to testify in related prosecutions; in return, the government, among other things, purported to grant him “retroactive use immunity” for his prior statements to the FBI, including his confession of the NCSC embezzlement and his disclosures in 1983.
In late March 1985, a short article in the interior pages of the Baltimore Sun reported that Kilroy had been indicted and described the charges. Several weeks later — before Kilroy confessed his embezzlement at NCSC — James Kim, NCSC’s controller, asked accountant Robert Williams to audit NCSC’s pension plan. On June 7, Williams reported to NCSC that he had reason to believe Kilroy had embezzled from the pension fund; by late September Williams had determined that the missing amount was $573,000 and advised NCSC that it must report the events to the federal Department of Labor. Throughout this time Williams was ignorant of Kilroy’s confession in Las Vegas.
On October 1, the Department of Labor opened a civil investigation of the NCSC affair. The Department’s investigator, James Pitt, met with NCSC staff and, in late October, reported his findings to Assistant United States Attorney Harry Benner of the U.S. Attorney’s office in the District of Columbia. Benner telephoned Stanley Parry, a special prosecutor with the Las Vegas team, who sent Benner a copy of Kilroy’s Las Vegas plea agreement. Parry also told Ben-ner that Kilroy had confessed to the NCSC embezzlement, but provided no further details. At the end of October, Benner met with Pitt, informed him of the plea agreement, and warned him to base his investigation on sources independent of the Las Vegas investigations.
Sometime in 1986, however, Pitt contacted FBI Agent Mark Kaspar, in charge of the Las Vegas investigations, and one of two agents to whom Kilroy had confessed his embezzlement. Kaspar refused to provide Pitt with records concerning Kilroy, but told Pitt of Kilroy’s admission; Kaspar added the warning that the admission fell within the government’s grant of immunity. By late 1987, Pitt had finished his civil investigation and compiled a report that recommended legal action against Kilroy. In February 1988, Pitt obtained records of Kilroy’s immunized statements from the Baltimore FBI office; apparently Pitt kept these documents separately from the civil investigatory file he had previously developed.
In December 1986, the Department of Labor opened a criminal investigation of the NCSC affair under the supervision of Robert Wagner. At the outset Benner told Wagner not to seek information from the FBI offices in Las Vegas or Baltimore and told him to warn those he interviewed not to reveal to him knowledge derived from immunized testimony. Wagner interviewed NCSC staff and, at the end of 1986, reviewed the civil files then compiled by Pitt. Informed by financial and tax records obtained from these sources, Wagner testified about Kilroy’s embezzlement before a grand jury in Washington, D.C., on March 31, 1987 and on February 23, March 2, and March 9, 1990. Wagner was the only witness to testify and did not relate any of Kilroy’s immunized statements. See United States v. Kilroy, 769 F.Supp. 6,10 & n. 7 (D.D.C.1991) (describing sources and content of Wagner’s testimony).
On March 26, 1990, the District of Columbia grand jury returned the indictment presently under review. Kilroy moved to dismiss the. indictment on several grounds. Pertinent to the present appeal, he sought either to quash the indictment or suppress substantially all of the evidence against him on grounds that it was derived either directly or indirectly from information he had imparted under the government’s promise of use immunity, in violation of the rule of Kastigar v. United States, 406 U.S. 441, 92 S.Ct. 1653, 32 L.Ed.2d 212 (1972). Benner and Wagner read all of Kilroy’s immunized statements in the FBI files in Las Vegas and Baltimore.1 Judge Jackson rejected all of Kilroy’s mo[683]*683tions in a published opinion. See Kilroy, 769 F.Supp. at 6. With reference to the Kasti-gar ground preserved for appeal, that is Kilroy’s claim that the indictment was obtained using “tainted” evidence .in violation of the immunity agreement, the district judge found that the indictment was entirely based on the testimony of Wagner, who appeared before the grand jury multiple times. The court further found that Wagner was at no time prior to his testimony privy to information developed in breach of the immunity agreement and thus could have imparted none to the grand jury.
II. The Legal FRAMEWORK
Kilroy’s argument rests on the principle, fundamental to our constitutional government, that a citizen is free “from governmental compulsion to testify against himself.” United States v. North, 910 F.2d 843, 853, reh’g granted in part, 920 F.2d 940 (D.C.Cir.1990), cert. denied, 500 U.S. 941, 111 S.Ct. 2235, 114 L.Ed.2d 477 (1991). Fundamental as the prohibition against the prosecution’s use of compelled testimony is, it is not absolute. Under 18 U.S.C. § 6002, the court may, upon the motion of the prosecution, compel a witness to testify even as to matters that incriminate him. However, the constitutionality of this compulsion depends upon the prohibition contained in the statute that “no testimony or other information compelled under the order (or any information directly or indirectly derived from such testimony or other information) may be used against the witness in any criminal case, except a prosecution for perjury, giving a false statement, or otherwise failing to comply with the order.” 18 U.S.C. § 6002. See Kastigar v. United States, 406 U.S. 441, 458, 92 S.Ct. 1653, 1663-64, 32 L.Ed.2d 212 (1971) (upholding the constitutionality of 18 U.S.C. § 6002 because the statutory “immunity from use and derivative use is coextensive with the scope of the [Fifth Amendment] privilege”).
The Kastigar decision is the seminal case in use immunity jurisprudence. Kasti-gar, as applied in this Circuit in North, provides the framework for analysis applicable to prosecutions of previously immunized witnesses: for a prosecution to proceed over the objection of an immunized witness, the court must hold a hearing in which the “heavy burden” is on the government to demonstrate “that it obtained all of the evidence it proposes to use [or has used] from sources independent of the compelled testimony.” North, 910 F.2d at 854. The parties and the district court assumed that the Kastigar framework applied in this, case. As this case involved an attempt to retroactively immunize statements, we question that proposition.
The purpose of the Kastigar hearing is to determine whether or not coerced testimony has been used against the witness in violation of his Fifth Amendment rights. See generally North, 910 F.2d at 853-73. A plea agreement that purports to immunize testimony already given can hardly have compelled that testimony, and the Kastigar framework seems ill-suited to analyze an allegation of the violation of such an immunity agreement. Neither this Circuit nor any other has ever analyzed this novel concept of “retroactive use immunity.” Only two district court opinions from a single district have alluded to “retroactive immunity.” Moreover, neither of them, even if authoritative, lends any support to a generalized acceptance of such a concept, or provides any framework for analysis. See United States v. Castellano, 610 F.Supp. 1137, 1140 (S.D.N.Y.1985) (noting without comment that an immunity order “was amended to grant ... retroactive immunity to [a prior] appearance,” by a witness other than the defendant in the case); United States v. Pellon, 475 F.Supp. 467, 480 (S.D.N.Y.1979) (noting that an agreement between the government and the defendant did not provide “retroactive use and derivative use immunity,” "without discussing whether and under what framework of legal analysis any such immunity can exist).
Troubled that the parties might be attempting to impose upon the court an improper frame of legal reference, we considered the possibility that proper examination might be under the rubric of Santobello v. New York, 404 U.S. 257, 92 S.Ct. 495, 30 L.Ed.2d 427 (1971), which provides the authority for determining whether or not the government has breached a plea agreement [684]*684and, if so, what the proper remedy is. Therefore, we directed supplemental briefing by the parties. We specifically requested the parties to address the following question:
When the United States and a criminal defendant have entered into a plea bargain purporting to afford use immunity to statements made before the agreement, and made in the absence of immunity agreement or other coercion, and a “use” has allegedly been made of the statement between the time of its then voluntary making and the entry of the agreement, is the allegation of improper use properly adjudicated under the standards set forth in Kastigar v. United States, 406 U.S. 441, 92 S.Ct. 1653, 32 L.Ed.2d 212 (1972), as a substitute compliance with the Fifth Amendment, or under the standards set forth in Santobello v. New York, 404 U.S. 257, 92 S.Ct. 495, 30 L.Ed.2d 427 (1971), as a remedy for breach of plea agreement?
In addition, we asked the parties to address “whether the plea agreement is a stipulation of fictitious facts, and, if so, can the Court bind itself by that stipulation in light of United States National Bank of Oregon v. Independent Insurance Agents of America, - U.S. -, 113 S.Ct. 2173, 124 L.Ed.2d 402 (1993)?” Inexplicably, the United States in its supplemental brief not only did not address the questions we submitted, but denied that the immunity agreement was retroactive at all, a position in direct contradiction to the entire prior history of the case, including not only the assumptions but the direct statements of the government’s principal brief. See, e.g., Brief of the United States at 2 (“Kilroy had retroactively received informal immunity for these statements pursuant to a plea agreement with the Las Vegas Strike Force.”) (emphasis added).
The United States chose instead to address the question of whether an “informal” immunity agreement is governed by the Kastigar standard as if it were a formal order of immunity under 18 U.S.C. § 6002. While that is a pertinent question, it is one adequately addressed by the United States in its principal brief, unlike the retroactivity question to which the court had directed response. Fortunately, the supplemental brief of the defendant/appellant and our independent research have been more helpful. It now appears that the initially applicable standard is stated in Santobello, but as to the ultimate result it will not make any difference.
In Santobello, a defendant alleged that the state had violated its plea agreement by arguing in favor of a maximum sentence after having agreed that no sentence recommendation would be made by the prosecutor. Upon a showing that the promise had been made and broken, the Supreme Court vacated the judgment and remanded, holding that “when a plea rests in any significant degree on a promise or agreement of the prosecutor, so that it can be said to be part of the inducement or consideration, such promise must be fulfilled.” Santobello, 404 U.S. at 262, 92 S.Ct. at 498-99.
In reviewing defense claims that a plea agreement has been made and broken, we have observed that “a plea agreement is a form of contract.” United States v. Pollard, 959 F.2d 1011, 1022 (D.C.Cir.1992). Thus, if we are analyzing Kilroy’s claims under San-tobello rather than Kastigar, instead of the government having the burden of proving that its case was untainted by improper use of compelled statements, the defendant would have the burden of proving that the plea bargain was made and breached. Appellant has admitted this burden, and we agree that it is the appropriate one.
As to the making of the bargain, appellant has no problem. Not only does the government concede it, but the evidence is of a piece that the bargain was entered. As to the breach, appellant faces a rather higher obstacle — in the end, an insurmountable one. The plea agreement did not provide Kilroy with any transactional immunity — that is, a promise that the government would not prosecute the instant offense.2 See United States [685]*685v. Poindexter, 859 F.2d 216, 219 (D.C.Cir.1988). Rather, the government only promised to give Kilroy “use immunity for all other information provided prior to his appearance before a grand jury.” The questions before first the district court and now this court are: (1) What did the agreement mean by “use immunity”? and (2) Did the government violate the protection afforded by that “use immunity”?
As to the first question, as the Ninth Circuit noted in United States v. Plummer, 941 F.2d 799, 804 (9th Cir.1991), the phrase “use immunity” is subject to at least two interpretations. “Use immunity” can mean that the communicant is protected against only direct use of his communication; or, it can mean that he is protected against even “indirect” use under a concept generally called “derivative use immunity.” Statutory immunity under § 6002 includes derivative use. “No testimony or other information compelled under the [immunity] order (or any information directly or indirectly derived from such testimony or other information) may be used against the witness.... ” 18 U.S.C. § 6002 (emphasis added). The Supreme Court in Kastigar held that the statute meant precisely what it said, and that, therefore, unlike some earlier immunity statutes, it is constitutional precisely because the immunity it provides “from use and derivative use is coextensive” with the Fifth Amendment privilege against self-incrimination. 406 U.S. at 453, 92 S.Ct. at 1661.3
The fact that the statute affords derivative use immunity does not, however, compel a conclusion that the plea agreement afforded more than a direct use immunity. As the Ninth Circuit observed in Plummer, “the Supreme Court’s thorough discussion of use immunity in Kastigar carefully distinguishes between use immunity and the broader derivative use immunity,” claimed by the defendant in Plummer and by Kilroy in this case. The district judge in Plummer, unlike the judge in the instant case, had held that the omission of the word “derivative” in the agreement unambiguously bespoke the narrower immunity against the direct use of the declarant’s statements. However, the Ninth Circuit observed that in the years since Kast-igar, a “common understanding” of the term “use immunity” has arisen “in the criminal justice world” expanding the term to encompass derivative use immunity. 941 F.2d at 804. We agree. .In the world since Kasti-gar, including our decision in North, the term “use immunity” has commonly been used to encompass the broader concept. For example, we stated in North “use immunity conferred under the statute is ‘coextensive with the scope of the privilege against self incrimination-910 F.2d at 854 (emphasis added), without specifying that we intended “derivative use immunity.” Consistent with that same understanding, we agree with the Ninth Circuit that nothing else appearing, an informal use immunity afforded by agreement, e.g,, a plea bargain, includes derivative use immunity equivalent to that afforded by the statute.
That said, we can discern no other standard by which we would judge whether or not a breach had occurred than the application of the Kastigar rule as explicated in North. Accordingly, even though the defendant has the theoretical burden of establishing breach, we will examine the evidence as if the government had the burden, because it has in effect entered a promise that said, “we will not use any evidence against you that we could not have used if the Kastigar test applied.” As Kastigar requires that the government will not use any evidence as to which it cannot meet the burden of proving that it was obtained independent of the defendant’s self-incriminating statements, a Santobello agreement purporting to grant use immunity effectively places a Kastigar burden on the government when that agreement has allegedly been breached. Therefore, to apply Santobello to the peculiar facts of this case, we must determine how Kasti-[686]*686gar would apply to the same alleged use of evidence.
III. Application
The task of the court under Kastigar, as applied in North, is often more easily stated than accomplished. The controlling question is: Has the government met its “heavy burden” of demonstrating ‘“that it obtained all the evidence it proposes to use [or has used] from sources independent of the compelled testimony.’ ” North, 910 F.2d at 854 (quoting Kastigar, 406 U.S. at 461-62, 92 S.Ct. at 1665-66). The district court was required to hold “a ‘Kastigar hearing’ for the purpose of allowing the government to demonstrate” that it had met that burden. North, 910 F.2d at 854 (internal parenthetical omitted). That demonstration is necessary both as to the evidence used before the grand jury to obtain the indictment, and the evidence that the government has used or intends to use at trial to obtain a conviction, depending upon whether the Kastigar hearing is held before or after the trial. See id. at 868-73.
Here the district judge held such a hearing. He made the appropriate finding as to the grand jury evidence that the “indictment ... was supported entirely by the testimony of a single witness before the grand jury,” and that that witness “at no time was ... privy to information developed by the government from Kilroy himself.” United States v. Kilroy, 769 F.Supp. at 10. The district court thus concluded that the witness imparted no tainted testimony to the grand jury in his four appearances before it. As to the grand jury evidence, we hold that this is a sufficient finding to establish that the government has met its burden of establishing by the greater weight of the evidence that it survived the Kastigar test.
In North, we directed that the inquiry on remand would “proceed witness by witness; if necessary, it will proceed line-by-line and item-by-item.” 910 F.2d at 872. Insofar as Kilroy intends to suggest that the district court did not follow the North standard, we disagree. When there is but one witness, the finding is inherently witness by witness. In North, our direction to proceed “line-by-line and item-by-item” was specifically only to be done where “necessary.” That case involved witnesses who were concededly exposed to the immunized testimony of the defendant, and further involved immunized testimony that was widely disseminated through the news media. This one does not. The district court’s finding here as to the single grand jury witness, a finding to be reviewed under a clearly erroneous standard, establishes the lack of necessity for further inquiry.
A conclusion that the government did not use tainted evidence in obtaining an indictment is, of course, not necessarily dispositive of a ease. The question remains as to whether the government could establish guilt beyond a reasonable doubt without the use of tainted evidence. See Kastigar, 406 U.S. at 461-62, 92 S.Ct. at 1665-66 (the government bears “the heavy burden of proving that all the evidence it proposes to use was derived from legitimate independent sources”) (emphasis added). Thus, in North, we directed the district court to conduct a review of the content and sources of both grand jury and trial witnesses’ testimony. See 910 F.2d at 872.
Here the district court considered the question of how the government intended to proceed at trial and determined “that the government ha[d], at least preliminarily, demonstrated the virtue of the case it propose[d] to offer against Kilroy.” 769 F.Supp. at 11. Kilroy argues that the district court’s finding is inadequate because it is by its very terms “preliminary.” He acknowledges that the district court held that the government did “have available to it both testimonial and documentary evidence sufficient to prove” its case against appellant “which would have (and did) come to light had Kilroy never” given his immunized testimony. But he contends these findings and conclusions by the district court are insufficient to meet the requirements of North because of the “preliminary” language employed by the court. Had this been the end of all, Kilroy might have a compelling argument. But the matter does not end there.
As we noted in North, “a trial court may hold a Kastigar hearing pre-trial, post-trial, [687]*687mid-trial (as evidence is offered), or it may employ some combination of these methods.” 910 F.2d at 859. Here Judge Jackson obviously intended to employ a combination of those methods. Having made a final determination as to the grand jury evidence, he preliminarily determined the question of trial evidence, deciding, no doubt wisely, to take that question up once again when the record became concrete and not merely predictive. Kilroy thus had the choice to plead not guilty and face a trial at which he could reopen the question, or to enter a conditional guilty plea and preserve the question for appeal on the then-existing record.4 Having chosen the second, he takes the record as to trial evidence as he finds it, and is stuck with the preliminary finding, which is adequate for the present determination.
Thus, unless the district court erred in its determination that there had been no use, Kilroy’s appeal fails. We examine that question under the “clearly erroneous” standard. United States v. North, 910 F.2d at 855. “A finding is not ‘clearly erroneous’ unless the reviewing court is left with the definite and firm conviction that a mistake has been made — the finding either is not supported by or is clearly against the weight of the evidence, or induced by an erroneous view of the law.” United States v. Sheard, 473 F.2d 139, 146 (D.C.Cir.1972). Here this is not the case. The district court’s finding is well supported on the record.
Kilroy’s argument to the contrary is rather convoluted. He sets forth certain facts: In late March 1985, a short article appeared in the interior pages of the Baltimore Sun reporting that Kilroy had been indicted in the Nevada case and describing the charges. Some weeks thereafter, James Kim, a private citizen and the controller of NCSC, directed an audit of the NCSC pension plan. Ultimately, the internal audit led to the determination that $573,000 was missing, a fact that NCSC was obligated to report to the Department of Labor. Some time after the commencement of the audit but befóte the criminal investigation which grew out of the referral to Labor, the retroactive immunity bargain was entered. Kilroy’s theory is that because the statements, about matters unrelated to the embezzlement, that the government purported to retroactively immunize in the plea agreement led to the indictment on the unrelated charges; and because that indictment was reported in the Baltimore Sun; and because the government cannot present direct evidence that Kim (now deceased) did not read the article in the Baltimore Sun, thus triggering his curiosity about the honesty of Kilroy; the investigation that ultimately led to the charges in the present case was based on a “use” of the immunized statement. We disagree.
Even recognizing, as we did in North, that the burden is the government’s to establish “that no use whatsoever was made of any immunized testimony,” the government has met its burden here. Wagner testified before the grand jury that “at a point in 1984 or ’85” the NCSC plan reached 100 participants, which under the Department of Justice regulations required NCSC to retain an outside accounting firm to audit the plan. On a record silent as to Mr. Kim’s residence but undisputed that he worked in Washington, D.C.; again silent as to whether or not he read the Baltimore Sun on the day in question — or for that matter ever — the district court’s finding that the government met its burden of establishing by the greater weight of the evidence that it obtained the indictment without any tainted use survives review. See North, 910 F.2d at 872. Accordingly, we conclude that the district court’s finding that Kim was “oblivious ... of Kilroy’s Las Vegas activities” at the critical time was supported by the evidence of record. Kilroy, 769 F.Supp. at 9.
As we did in North, we assume, without deciding, “that a prosecutor cannot make nonevidentiary use of immunized testimony,” any more than evidentiary use, without running afoul of use immunity. Id. at 860. In so doing, we recognize, as we did in North, that Kastigar compels that immunity [688]*688be “coextensive with the Fifth Amendment” in order to satisfy constitutional demands. Id. at 859. However, neither Kastigar nor North nor any other authority with which we are familiar compels a conclusion that the use immunity conferred under the statute or by agreement must broadly exceed that afforded by the Fifth Amendment. Neither are we familiar with any authoritative interpretation of the Fifth Amendment holding that a defendant cannot be indicted on wholly unrelated charges based on evidence wholly unrelated to a compelled confession, simply because the second indictment occurs after a first that was obtained in violation of the defendant’s Fifth Amendment rights.
Kilroy would claim that he has done more than establish a post hoc, ergo propter hoc relationship between the second indictment and the first, and therefore between the second prosecution and the use of the testimony. His argument rests on the premise that there is a “but for” relationship between the second indictment and the first5 — a relationship dependent upon the pure speculation that the investigation underlying the present indictment would never have occurred but for the first indictment which would not have occurred but for the immunized, statements. That speculation is nothing more than a reformulated recital of the temporal order argument already rejected.
The nearest analogous actual case we have found to Kilroy’s concept of “use” is the one rejected in United States v. Helmsley, 941 F.2d 71 (2d Cir.1991). In that case, the Second Circuit accepted arguendo an appellant’s recitation of fact that she had appeared twice before state grand juries to give immunized testimony concerning a state tax avoidance scheme; a New York Post reporter read a New York Times article implicating her in the state tax avoidance scheme; the information in the Times article rekindled the Post reporter’s interest in a previous tip about the misuse of corporate funds by Helmsley and her husband; the Post published an article stating that the Helmsleys had used false invoices to pay personal expenses with corporate funds; that article triggered investigation by the United States Attorney for the Southern District of New York and other authorities, which led to a federal indictment. See id. at 77-78, 81.
In rejecting a Kastigar challenge to Helmsley’s conviction on the new indictment, the Second Circuit held that the triggering of the decision of an independent party to “reopen his earlier investigation” based on “his perception of a ‘morality connection’ ” and his happening upon an incriminating witness as a result did not constitute a tainted use. Id. at 83. The court held that nothing in existing authority6 “suggested] that the Fifth Amendment applies to situations in which the publicity concerning immunized testimony triggers a purely private investigation into an entirely different matter solely because each matter involved dishonest conduct.” Id. We agree with the Second Circuit. Applying the Helmsley reasoning to the present record, even if Mr. Kim became generically suspicious of the moral quality of his employer’s fiduciary because that fiduciary came under indictment based on immunized statements in an unrelated matter, it tortures the concept of “use” out of all semantic regularity to suppose that the tainted statement was “used” in obtaining the second indictment.
Accordingly, we conclude that the district court did not err, and certainly did not clearly err, in its finding that there was no use of [689]*689the immunized testimony in the present case.7
IV. Conclusion
For the reasons set forth above, we conclude that the district court committed no error in denying Kilroy’s motion to dismiss. The judgment appealed from is therefore
Affirmed.