ON RELATORS' PETITION FOR WRIT OF MANDAMUS
BUTTS, Justice.
PETITION FOR WRIT OF MANDAMUS CONDITIONALLY GRANTED
This original mandamus proceeding arises out of two libel actions against rela-tors.1 Respondent, Ricardo H. Garcia, judge of the 229th District Court of Starr County, has ordered relators to disclose to the libel plaintiffs the identity of the sources used in the preparation of the articles. Relators have asked for a writ of mandamus directing Judge Garcia to rescind his order compelling disclosure. They argue that he has abused his discretion because the identities of their sources are confidential and are protected from compelled disclosure by the journalist’s privilege. We conditionally grant the writ of mandamus.
The libel actions are based on a series of news articles entitled, “Texas’ Little Columbia,” investigating illegal drug trafficking in Starr and Hidalgo Counties. These counties border Mexico along the Rio Grande River. The series consisted of 20 articles that ran in the Morning News October 14 through 19, 1990. Plaintiffs complain that they were libeled by the nine articles in the series published on October 14, 15, and 17.
The first libel action, cause number 8845, was brought by the parents of Eloy Garza, Jr. as his next friends.2 Garza claims he was libeled in an article published on October 15, 1990. This article attempted to show how the drug trade and drug money had corrupted various government officials in Starr and Hidalgo counties. One sentence in the article falsely stated that Eloy Garza, Jr. had pleaded guilty to possession of small amounts of cocaine and marijuana. His father, Eloy Garza, Sr., is a county commissioner in Starr County. Discovering that the guilty party was another Eloy Garza, Jr., and not the commissioner’s son, who was six years old at the time, the Morning News printed a retraction.
The plaintiff in cause number 8846, the second libel action, is Gene Falcon, Sheriff of Starr County. One article in the series, published October 17, 1990 (the Falcon article), featured Sheriff Falcon. Falcon claims that this article falsely accused him by innuendo and by direct allegation of having been involved with drug trafficking and other illegal activity. He further claims that the articles published on October 14 and 15 libeled him by accusing him of the commission of criminal acts.
The Falcon article accused the sheriff of being friends with drug dealers and other criminals, of making little effort to combat drug trafficking in the county, of associating with an alleged drug kingpin, and of rerouting patrols to let drug shipments pass through the county unmolested. These accusations were attributed to sources such as “observers,” “local residents,” “ex-drug dealers,” and “former deputies.” The article mentioned that Falcon had been charged in Mexico for the drug-related murder of a hospitalized Mexican prisoner, and that Mexican authorities had issued a warrant for his arrest. The article also charged that the sheriff had purchased a large home in Starr County for less than its appraised value, and that the [678]*678home had been owned previously by the wife of Ramon Garcia Rodriguez, who was identified in the article as “an alleged drug kingpin and federal fugitive.”
Relators pleaded that the articles are true, that they were not published with actual malice, that they are not actionable because they are statements of opinion, that they are privileged as fair comment or criticism under Tex.Civ.PRAC. & Rem.Code Ann. § 73.002(b)(2) (Vernon 1986), that they are privileged because they are neutral reporting by responsible persons or organizations on matters of legitimate public interest, and that plaintiffs have not been damaged.
Plaintiffs filed a series of interrogatories and requests for production in which they sought the names of all third-party sources that were interviewed, or from whom statements were obtained or relied upon in preparing the nine articles. Relators assert that they have answered each interrogatory except those that would lead to disclosure of their confidential sources. They also claim that they have produced all requested documentary information, except that the names of their confidential sources have been expunged from the documents provided.
Plaintiffs filed motions to compel responses to their interrogatories and requests for production. In response, rela-tors asserted that the information requested was protected by the journalist’s privilege against forced disclosure of confidential sources.
A hearing was held on the motions to compel. In each case the court found that relators failed to prove the existence of their privilege; that the identities of the confidential sources for the articles in question (October 14, 15, and 17 in the Falcon case, and October 15 in the Garza case) are highly relevant and material, and necessary and critical to the trial of plaintiffs’ cases; that there are no other means available to determine the confidential sources; and that plaintiffs have exhausted all available means to determine the identity of the sources.
In the Falcon case, respondent granted plaintiff’s motion to compel in each particular, except one. Relators were not ordered to disclose confidential sources who are former Starr County sheriff’s deputies because the court found that Falcon had not exhausted all available means to determine their identities. The Garza motion was granted in its entirety. Except for the former deputies, relators were ordered to disclose their sources for all nine articles.
I. THE JOURNALIST’S PRIVILEGE
In Branzburg v. Hayes, 408 U.S. 665, 92 S.Ct. 2646, 33 L.Ed.2d 626 (1972) the Supreme Court held that a journalist does not have an absolute privilege under the First Amendment to refuse to disclose confidential sources to a grand jury conducting a criminal investigation. The court, however, explicitly recognized that news gathering is not without first amendment protection. 408 U.S. at 707, 92 S.Ct. at 2670. “[Wjithout some protection for seeking out the news, freedom of the press could be eviscerated.” Id. at 681, 92 S.Ct. at 2656. Since Branzburg, the courts have recognized a qualified First Amendment privilege against compelled disclosure of confidential information possessed by a journalist. Miller v. Transamerican Press, Inc., 621 F.2d 721, 725 (5th Cir.), modified on rehearing, 628 F.2d 932 (5th Cir.1980), cert. denied, 450 U.S. 1041, 101 S.Ct. 1759, 68 L.Ed.2d 238 (1981).
The qualified privilege is also grounded in Tex.Const. art. I, § 8, the free speech and press clause. Channel Two Television Co. v. Dickerson, 725 S.W.2d 470, 472 (Tex.App.—Houston [1st Dist.] 1987, no writ). Given the overriding importance to our society of a free press, we feel it is important to emphasize that our decision today is based on both the First Amendment of the federal constitution and on article I, section 8 of our own constitution. See Channel Two, 725 S.W.2d at 472-73 (Levy, J., concurring).
Falcon’s attorney admitted the existence of the qualified privilege at the hearing on the motion to compel. At issue is the application of the privilege to the [679]*679facts and circumstances of this case. The courts will look to the facts on a case-by-case basis in the course of balancing the need for the testimony in question against the claims of the news gatherer that the public’s right to know is impaired. Carey v. Hume, 492 F.2d 631, 636 (D.C.Cir.), cert. dismissed, 417 U.S. 938, 94 S.Ct. 2654, 41 L.Ed.2d 661 (1974). See also Branzburg, 408 U.S. at 710, 92 S.Ct. at 2671 (Powell, J., concurring). When striking this balance, we are mindful of the preferred position of the First Amendment and the importance of a vigorous and unfettered press. Zerilli v. Smith, 656 F.2d 705, 712 (D.C.Cir.1981). We are also aware that the duty of a witness to testify in a court of law, and the correlative right of a litigant to obtain judicial compulsion of that testimony, are essential to the fabric of our society. Garland v. Torre, 259 F.2d 545, 548-49 (2d Cir.), cert. denied, 358 U.S. 910, 79 S.Ct. 237, 3 L.Ed.2d 231 (1958).
II. PROPRIETY OF MANDAMUS
Mandamus is an appropriate remedy when a party is harmed by an order requiring the disclosure of privileged material. West v. Solito, 563 S.W.2d 240, 244 (Tex.1978). A trial court order that compels disclosure of privileged matters constitutes an abuse of discretion which may be corrected by mandamus. Wal-Mart Stores, Inc. v. Street, 754 S.W.2d 153, 155 (Tex.1988). “The test for abuse of discretion is whether the trial court acted without reference to any guiding rules or principles; in other words, whether the act was arbitrary or unreasonable.” Worford v. Stamper, 801 S.W.2d 108, 109 (Tex.1990). “In order to find an abuse of discretion, the reviewing court must conclude that the facts and circumstances of the case extinguish any discretion in the matter.” Johnson v. Fourth Court of Appeals, 700 S.W.2d 916, 918 (Tex.1985).
III. RELATORS' BURDEN
The burden of proof to establish the existence of a privilege rests on the party asserting it. Jordan v. Fourth Court of Appeals, 701 S.W.2d 644, 648-49 (Tex.1985). The party resisting discovery must produce evidence supporting the particular privilege, immunity or exclusion claimed. Tex.R.Civ.P. 166b(4); Weisel Enterprises, Inc. v. Curry, 718 S.W.2d 56, 58 (Tex.1986); Channel Two, 725 S.W.2d at 472. The evidence may be in the form of affidavits or live testimony. Rule 166b(4).
Relators have met this burden. Their proof consisted, in part, of the affidavits of the three reporters who authored the articles complained of. They stated in their affidavits that they are reporters employed by the Morning News, and that in the course of preparing the articles they assured certain news sources that they would keep their identities and certain information they provided confidential.3
Plaintiffs cite language in Channel Two in arguing that relators had the burden to tender the information sought to be protected to the trial court for an in camera inspection. Relators did not do this. Channel Two mentions this requirement, but does not indicate whether materials were produced in that case. 725 S.W.2d at 472.
An in camera inspection was not required. When a party seeks to exclude materials from discovery on the basis of the invasion of constitutional rights, an in camera inspection is not necessary. Tex. R.CiV-P. 166b(4); Hoffman v. Fifth Court of Appeals, 756 S.W.2d 723, 723 (Tex.1988). Further, plaintiffs’ purpose in these proceedings has been to obtain the names of relators’ confidential sources. A mere list of names would not help respondent deter[680]*680mine whether those persons were the confidential sources relied upon by the reporters. The issue is not who the sources are, but whether disclosure of their identities will be compelled.
IY. PLAINTIFFS’ BURDEN
Once the journalists’ privilege has been asserted, the burden of producing substantial evidence sufficient to overcome the privilege shifts to the party seeking discovery. In re Selcraig, 705 F.2d 789, 792 (5th Cir.1983); Channel Two, 725 S.W.2d at 472. Plaintiffs’ attorneys admitted at oral submission that the burden had shifted to them.
Because the journalist’s privilege is a qualified one, it can be overcome in certain circumstances. It can be overcome in libel cases if the party who seeks disclosure establishes by substantial evidence (1) that the statement attributed to the informant was published and is false and defamatory; (2) that reasonable efforts have been made to learn the informant’s identity by alternative means, but that no other reasonable means is available; and (3) that knowledge of the informant’s identity is necessary or critical to proper preparation and presentation of the case. Selcraig, 705 F.2d at 792; Miller, 628 F.2d at 932. This last element is sometimes expressed in terms of whether there is a “compelling interest” in the information. LaRouche v. National Broadcasting Co., 780 F.2d 1134, 1139 (4th Cir.), cert. denied, 479 U.S. 818, 107 S.Ct. 79, 93 L.Ed.2d 34 (1986); Miller, 621 F.2d at 726.
Plaintiffs again turn to Channel Two to support their argument that they are not required to offer substantial evidence of the falsity of the statements. But Channel Two does not mention that requirement. That case was decided in favor of the privilege based on the plaintiff’s failure to make a showing that the information sought met the other criteria of the test. 725 S.W.2d at 472.
Several cases, including Channel Two, 725 S.W.2d at 472, require a showing that the identities of the confidential sources are “highly material and relevant.” Channel Two includes this requirement in place of the “falsity” requirement. In setting out its three-prong test, Channel Two relies on the initial Miller opinion. Miller, 621 F.2d at 726. On rehearing, the Fifth Circuit modified the test set out in its initial opinion by deleting the relevancy requirement and adding the “substantial evidence of falsity” requirement. Miller, 628 F.2d at 932. The Fifth Circuit has since reaffirmed the modified Miller test. Selcraig, 705 F.2d at 792. That is the test we adopt today. We believe it strikes the proper balance between the obligation of all citizens to give relevant testimony and the freedom of the press as guaranteed in the federal and Texas constitutions. See Branzburg, 408 U.S. at 710, 92 S.Ct. at 2671 (Powell, J., concurring).
The deletion of “relevancy” as a separate requirement does not significantly alter the plaintiff’s burden of proof. “Relevancy” is no more than the standard established in Carey that the sources’ identities must “go to the heart” of the plaintiff’s libel claim. 492 F.2d at 636. In other words, the information sought must be “critical” to the plaintiff’s case. Id. at 637. The relevancy requirement adds nothing to the test that is not already encompassed in the “necessary or critical” element. If the information is necessary or critical to the plaintiff’s case, it follows that it is also highly material and relevant. Significantly, Carey discussed these elements together, holding that the information sought must go to the heart of the plaintiff’s libel action, and finding that the identities of the defendants’ sources in that case were critical to the plaintiff’s claim. 492 F.2d at 636-37.
Plaintiffs argue that at the most their burden is satisfied by a “minimal” showing that their suit is neither frivolous, nor manufactured as a pretense for a discovery request. They cite Zerilli, and Bruno & Stillman, Inc. v. Globe Newspaper Co., 633 F.2d 583, 597 (1st Cir.1980). They apparently seize on the use of the word “frivolous” in those cases as an indication that the proof required is frivolous, in the sense of “trivial” or “inconsequential.” “Frivolous” does not describe the [681]*681amount of proof required, but rather the substance or nature of the suit. The burden to refute the “frivolousness” of a libel suit is neither a minimal nor a trivial one; it requires the plaintiff to establish by substantial evidence that the informants’ statements are false and defamatory.
In Zerilli, the court of appeals affirmed the district court’s denial of the appellants’ motion to compel discovery. While the opinion noted in passing that the appellants’ suit was not frivolous, the case turned on the fact that the appellants had not exhausted possible alternative sources of the information. 656 F.2d at 714.
Bruno & Stillman indicates that the plaintiff must show, as a threshold matter, that its “claim is not frivolous, a pretense for using discovery powers in a fishing expedition.” 633 F.2d at 597. It then provides some guidelines for making this showing. The plaintiff must show that it can raise jury issues on the essential elements of its case. For example, the falsity of the news gatherer’s charges should be drawn into question and established as a jury issue before discovery of the confidential sources will be compelled. Id.
This principle is further illustrated in Cervantes v. Time, Inc., 464 F.2d 986 (8th Cir.1972), cert. denied, 409 U.S. 1125, 93 S.Ct. 939, 35 L.Ed.2d 257 (1973). Disclosure will not be compelled until there is a “concrete demonstration” that the identity of the sources will lead to persuasive evidence on the issue of malice. 464 F.2d at 994. If, during the course of discovery, the plaintiff uncovers substantial evidence tending to show that the published assertions are so inherently improbable or are untrue, the reasons favoring compulsory disclosure are more compelling. Id.
The requirement that substantial evidence of falsity must be shown is designed as a threshold criterion in order to prevent forced disclosure of confidential sources based on a mere pleading that the plaintiff has been injured by an untrue statement. See Miller, 628 F.2d at 932.
The point of principal importance is that there must be a showing of cognizable prejudice before the failure to permit examination of anonymous news sources can rise to the level of error. Mere speculation or conjecture about the fruits of such examination simply will not suffice.
Cervantes, 464 F.2d at 994.
The courts in journalist privilege cases recognize the heavy burden a public official has to meet in order to prove libel. Plaintiffs in those cases must prove “actual malice” — that the statement was made with knowledge of its falsity or with reckless disregard of whether it was false or not. New York Times v. Sullivan, 376 U.S. 254, 279-80, 84 S.Ct. 710, 726, 11 L.Ed.2d 686 (1964). Frequently, proof of actual malice will depend on knowing the informant’s identity, because the plaintiff will have to show that the informant was unreliable and that the journalist failed to take adequate steps verify his story. Zerilli, 656 F.2d at 714. See also, Herbert v. Lando, 441 U.S. 153, 170, 174, 99 S.Ct. 1635, 1645, 1648, 60 L.Ed.2d 115 (1979) (defamation case involving disclosure of defendants’ “editorial processes”); Carey, 492 F.2d at 634. Even Garza, who is not a public figure, must meet the Sullivan standard in order to recover the exemplary damages he seeks. Gertz v. Welch, 418 U.S. 323, 350, 94 S.Ct. 2997, 3012, 41 L.Ed.2d 789 (1974).
Yet the courts are also jealous guardians of the press freedoms guaranteed in the First Amendment.
In the ordinary case the civil litigant’s interest in disclosure should yield to the journalist’s privilege. Indeed, if the privilege does not prevail in all but the most exceptional cases, its value will be substantially diminished. Unless potential sources are confident that compelled disclosure is unlikely, they will be reluctant to disclose any confidential information to reporters.
Zerilli, 656 F.2d at 712.4 It is the citizenry’s interest, after all, in the full and free [682]*682flow of information and ideas that is the basis for the Constitution’s protection of the press. “Enlightened choice by an informed citizenry is the basic ideal upon which an open society is premised, and a free press is thus indispensable to a free society.” Branzburg, 408 U.S. at 726, 92 S.Ct. at 2672 (Stewart, J., dissenting) (footnote omitted). The guarantee of a free press is “not for the benefit of the press so much as for the benefit of all of us.” Time, Inc. v. Hill, 385 U.S. 374, 389, 87 S.Ct. 534, 543, 17 L.Ed.2d 456 (1967).
The burden imposed in Bruno & Stillman, Cervantes, and Miller goes beyond a “minimal” showing that the libel suit is not frivolous or manufactured. If the plaintiff cannot at a minimum produce enough evidence to establish the probable falsity of the defendant’s statements, he may not, at the expense of the defendant’s constitutional rights, conduct a fishing expedition through its confidential sources in an effort to contrive such a claim.5
V. HAVE PLAINTIFFS MET THEIR BURDEN?
A. Substantial evidence of falsity.
Falcon testified at the hearing on the motion to compel that the statements attributed to confidential sources in the Falcon article are, in his opinion, false. The article contained a statement that a Mexican judge had raised some questions regarding the legality of the dismissal of murder charges against Falcon in Mexico. Falcon testified that this statement was false. He also testified that he was not aware that one of the record owners of the house he purchased was the wife of Ramon Garcia Rodriguez, the alleged drug kingpin. This is all the proof he offered. It should be noted that the Mexican judge was identified in the article, and that none of the story relating to the purchase of the home was attributed to o confidential sources.
Relators have included in the record the documentary evidence they produced at discovery. The evidence includes banking and real estate documents relating to Falcon’s purchase of the home, and an interview with the Mexican judge. Falcon admits that he was a suspect in the murder and that murder charges were filed against him in Mexico. Sources specifically connecting Falcon with illegal drug trafficking are identified in the documents.
That Falcon’s proof falls well short of substantial evidence of falsity can be illustrated by comparing his proof with that offered by the plaintiff in Cervantes. In that case, the mayor of St. Louis sued Life magazine contending that four paragraphs of an 87 paragraph article libeled him by asserting that he had personal ties to organized crime. Mayor Cervantes “undertook extensive pretrial discovery,” including the deposition of the reporter who gathered the information that formed the basis for most of the story. 464 F.2d at 988. When the reporter refused to disclose his sources, the mayor filed a motion to compel disclosure. Life responded by moving for summary judgment on the grounds that it had acted in good faith in publishing the article and that it believed the statements to be true. The district court granted the motion for summary judgment.
To rebut substantial evidence submitted by Life documenting that the information [683]*683for the article was carefully compiled and verified, the mayor presented “little more than a series of self-serving affidavits ... together with other evidentiary materials which framed but a minimal assault on the truth of the matters contained in the four paragraphs.” 464 F.2d at 994. The mayor apparently put on more proof than Falcon, yet his motion to compel disclosure was not even reached. Rather, Life’s motion for summary judgment was affirmed.
Falcon’s self-serving opinion testimony does not meet the requirement of substantial evidence. Indeed, it is even difficult to stretch it to meet the “minimal” burden plaintiffs set for themselves. Every plaintiff in every libel case will testify that he or she believes the published statements are false. If this were the only requirement, the qualified privilege would be no privilege at all; anyone could overcome it merely by filing a libel suit and expressing the opinion that the defendant’s statements were false.
Garza’s case is different, however, in that relators have admitted the falsity of the sentence mentioning Garza, Jr. The substantial evidence of falsity test has been met. Even for Garza, however, the inquiry is not at an end. Like Falcon, before he can obtain an order compelling discovery, he must also meet the two remaining requirements of his burden of proof.
B. Exhaustion of alternative sources of information.
Falcon testified that he has made inquiries among different people but has been unsuccessful in locating the confidential sources. Falcon’s attorney testified that Falcon had made “substantial” efforts to identify the sources — he “talked apparently to people and made inquiries. He said Falcon was unable to contact the presumed sources because he could not confirm that they were the confidential sources. The attorney indicated that he considered it futile to attempt to depose presumed sources until it is known for sure that they are the confidential sources relied upon by relators.
Falcon’s attorney admitted that relators have furnished at least 48 names of persons having knowledge of relevant facts. Relators have also included in the record a vast amount of documentary evidence that they produced at discovery. Further, sources linking Falcon to illegal drug trafficking were identified in those documents. In the face of this wealth of information, Falcon has taken only one deposition, that of Gayle Reaves. Ms. Reaves continually refused to identify her sources.6
Falcon’s attorney testified that the attorneys for both sides had agreed to depose the reporters before anyone else. Such an agreement, however, has been held insufficient to override the First Amendment’s protection of confidential sources. Liberty Lobby, Inc. v. Rees, 111 F.R.D. 19, 22 (D.D.C.1986). In any event, they deposed only one reporter before they filed their motion to compel.
It is apparent that Falcon abandoned any attempts to discover alternative sources in favor of his motion to compel. Perhaps the most damning testimony came from Falcon’s counsel when he was being cross-examined about efforts made to locate and depose confidential sources. He said, “I made the decision as an attorney for Sheriff Falcon to wait and find out who the confidential sources are when the newspaper discloses it.” This court will not sanc[684]*684tion the use of a motion to compel disclosure of confidential sources as a preliminary discovery matter rather than as a “last resort.” See Carey, 492 F.2d at 638 (compelled disclosure of confidential sources is “normally the end, and not the beginning, of the inquiry.”); Mize v. McGraw-Hill, Inc., 82 F.R.D. 475, 478 (S.D.Tex.1979).
Garza’s attorney testified that in an effort to locate the source of the statement about Garza, Jr., he examined the criminal record of the Eloy Garza, Jr. who had pleaded guilty. He also talked to the persons who were involved in the case of the other Garza, Jr. — the district attorney, the defense attorney, the officers involved in the arrest, and the probation officer. None admitted to being the source.
It would seem that David Hanners, author of the sentence about Garza, Jr., would be another logical source of information. Hanners, however, has not been deposed. See LaRouche, 780 F.2d at 1139. Garza’s attorney indicated that he believed Hanners would also refuse to answer any questions regarding the identity of confidential sources. The attorney’s belief is not substantial evidence that Hanners would refuse to answer, or would refuse to provide information that would lead to discovery of the identity of the source.
Garza’s attorney admitted that the only statement Garza is complaining of is the one in the October 15 article accusing Garza, Jr. of possession of illegal drugs. He asserted that he nevertheless is seeking the identity of all sources that contributed to any part of that particular article. He has not offered proof of any attempt to exhaust alternative means of locating these sources.
We conclude that Falcon’s attempts to exhaust alternative sources of information were inadequate. His primary proof comes from the testimony of his attorney. The only other evidence is Falcon’s testimony that he had talked to people and made inquiries. This is not substantial evidence of exhaustion of all alternative means. Aside from his deposition of Ms. Reaves, Falcon has not shown that he has made any effort to use the information provided by relators.7
Garza, on the other hand, has made a more exhaustive effort to locate the source who identified him as the person who pleaded guilty to possession of illegal drugs. We cannot hold that his investigation is complete, however, until he has at least taken the obvious step of deposing the author of the allegedly libelous sentence. We reiterate, however, that Garza has offered no evidence that he has exhausted alternative means of discovering the identities of the remaining sources for the article that mentions him.
C. Material or critical need for the information.
Plaintiffs sought disclosure of all sources for all nine articles even though only one article — and possibly a paragraph in another article — focused on Falcon, and only one sentence mentioned Garza, Jr. The reporters stated in their affidavits that many sources provided information wholly unrelated to Falcon, and that only one confidential source provided information about the statement relating to Garza, Jr. Yet the orders in question compel disclosure of every confidential source who contributed to each of the nine articles, with no attempt to distinguish sources who provided information about plaintiffs and sources who had nothing at all to say about them.
The matters attributable to the confidential source must be material and critical to the plaintiff’s case; that is, they must go to the heart of the case and be central to the issue of the alleged def[685]*685amation. Carey, 492 F.2d at 636; Garland, 259 F.2d at 550; Liberty Lobby, 111 F.R.D. at 21-22. Disclosure of confidential sources whose testimony would go only to a collateral issue, or to one not essential to the plaintiff’s case-in-chief will not be permitted. Dowd v. Calabrese, 577 F.Supp. 238, 245 (D.D.C.1983); Liberty Lobby, 111 F.R.D. at 22. Plaintiffs have not shown a compelling need for the disclosure of the confidential sources who provided no information about them. They have not demonstrated that this information is highly material and relevant, or necessary or critical to their libel claims.
Garza sought the names of all the sources for the article that mentioned Garza in order to determine whether the reporters were generally responsible in their reliance on these sources in writing that article. But the issue in Garza’s case is not whether the reporters are generally responsible and careful, but whether Han-ners was responsible and careful in relying on the source who provided the particular information that allegedly libeled Garza. Garza has not shown a critical need for these collateral sources.
In addition, Falcon has not shown by substantial evidence a material or critical need for the identities of the particular sources who provided information about him. It may be that he can establish a case for actual malice based on the 48 disclosed but undeposed sources, or on the other information provided by relators during discovery. See Miller, 621 F.2d at 726 (“it will often be possible to establish malice or lack of malice without disclosure of the identity of the informant.”). Even if he cannot, he must first make the attempt before disclosure of confidential sources will be compelled. Liberty Lobby, 111 F.R.D. at 22. Compelled disclosure is “a last resort after pursuit of other opportunities has failed.” Carey, 492 F.2d at 639.
Again, we reach a different determination in the Garza case. Many of the cases ordering disclosure have done so on the basis that the defendants’ only source for the allegedly libelous statements is the informant. Miller, 621 F.2d at 726; Carey, 492 F.2d at 637; Garland, 259 F.2d at 547. Hanners got his information about Garza, Jr. from the court records and from one confidential source. It is crucial to Garza’s proof of malice to interview the source to determine whether Hanners was reasonable in his reliance on the source.
VI. CONCLUSION
Falcon has failed to offer substantial proof of the falsity of the allegations attributable to confidential sources. Rela-tors admit, however, that the statement regarding Garza, Jr. was false.
Neither of the plaintiffs has shown that he has exhausted all alternative means of learning the identities of the sources. Falcon has made little effort at all, choosing to rely on his motion to compel. Garza has neglected to depose the author of the allegedly libelous statement.
Neither plaintiff has made a showing of material or critical need for the identities of collateral sources — those sources who did not provide information about them. Nor can we say at this point that Falcon has shown a material or critical need even for the identities of the sources who provide information about him. He has not demonstrated that he is unable to make his case without the identities of these sources. Garza, however, has shown a critical need, but only for the one source who provided information relating to the statement he alleges has libeled him.
We do not say that plaintiffs will never be entitled to disclosure of the identities of the confidential sources, only that they have so far failed to make a case for disclosure. But we also reiterate and emphasize that disclosure of confidential sources will be compelled only as a last resort after pursuit of all other opportunities has failed.
In light of plaintiffs’ failure to meet their burden in support of disclosure, we conclude that the trial court abused its discretion by ordering disclosure of the identities of the confidential sources. The petition for writ of mandamus is conditionally granted. We are confident that Judge Garcia will vacate his September 5,1991 orders granting plaintiffs’ motions to compel dis[686]*686covery in cause numbers 8845 and 8846. The writ will issue only if he fails to do so.