SILBERMAN, Circuit Judge:
Dow Jones & Company, Ire. appeals from the judgment of the district court denying it access under the Freedom of Information Act ("FOIA"), 5 U.S.C. § 552, to redacted portions of a letter sent by the Justice Department to the House Committee on Standards of Official Conduct (the "House Ethics Committee"). The letter summarized the results of a Justice Department probe into possible criminal wrongdoing by Fernand J. St Germain, who at the time was a member of Congress and Chairman of the House Committee on Banking, Finance, and Urban Affairs. The Department had declined to pursue an indictment, but it decided to inform the House Ethics Committee about the information it had collected. Because we conclude that the redacted information was obtained from confidential sources in the course of a criminal investigation, we affirm the district court's judgment that the entire redacted portion of the letter is exempt from disclosure under FOIA.
I.
On May 31, 1988, John C. Keeney, the Acting Assistant Attorney General of the Criminal Division of the Justice Department, sent a letter to Representative Julian C. Dixon, Chairman of the House Ethics Committee. The letter revealed that the Justice Department had been conducting a grand jury investigation into whether Representative St Germain's receipt of free meals and entertainment was in violation of any criminal laws. The Department explained that "because certain technical requirements of the relevant statutes make it uncertain that [the Department] would be able to meet the standard of proof of guilt beyond a reasonable doubt," it had declined to prosecute. But the Department also stated in the letter that the investigation had uncovered "substantial evidence of serious and sustained misconduct by Representative St Germain," and the Department explained that it was therefore referring the matter to the Ethics Committee to determine whether any House standards of conduct had been violated. Crucially for this case, the letter outlined some of the information the Department had obtained in interviews conducted in the course of the investigation.
On July 28, 1988, Dow Jones requested a copy of the letter under FOIA. Approximately one month later, the Justice Department, relying on the privacy-based exemptions under the statute, declined to release the letter. In November, Dow Jones filed suit in the district court to compel disclosure.
The district court granted the Department's motion for summary judgment, sustaining the Department's denial of the FOIA request. See Dow Jones & Co., Inc. v. Department of Justice, 724 F.Supp. 985 (D.D.C.1989). The court held that the Department could properly withhold the redacted portion under Exemption 5 of FOIA, 5 U.S.C. § 552(b)(5), which excludes from disclosure certain "inter-agency" and "intra-agency" documents that reflect an agency's deliberative process. See id. at 989. That interpretation of Exemption 5 would bar completely disclosure of the redacted portion of the letter; nevertheless, as a prudential matter, the court went on to consider the applicability of other FOIA exemptions .asserted by the government.
The district court decided that Exemption 7(C), 5 U.S.C. § 552(b)(7)(C), which excludes documents the production of which "could reasonably be expected to constitute an unwarranted invasion of personal privacy," permitted the withholding of the names of the witnesses but not the substance of the interviews. See 724 F.Supp. at 991. And the court concluded that Exemption 7(D), 5 U.S.C. § 552(b)(7)(D), which protects information obtained from confidential sources in the course of a criminal investigation, would shield only the identities of and information provided by the Department's "primary witness and the primary witness' associate." 724 F.Supp. at 992. The Department, according to the court, did not establish that the other witnesses were "confidential sources," and therefore the redacted parts of the letter discussing information provided by these nonconfidential sources would have had to have been released if the Department had relied only on Exemption 7(D). See id.
Dow Jones challenges all of the district court's determinations. The Department, however, has chosen to defend the court's judgment only on Exemptions 5 and 7(D) grounds — it has dropped the Exemption 7(C) claim.
II.
Under FOIA, "virtually every document generated by an agency is available to the public in one form or another, unless it falls within one of the Act's nine exemptions." NLRB v. Sears, Roebuck & Co., 421 U.S. 132, 136, 95 S.Ct. 1504, 1509, 44 L.Ed.2d 29 (1975). Exemption 5 of the statute permits an agency to refuse to disclose to the public "inter-agency or intraagency memorandums or letters which would not be available by law to a party other than an agency in litigation with the agency." 5 U.S.C. § 552(b)(5). Since litigants can obtain virtually any unprivileged document, "[cjourts have construed this exemption to encompass the protections traditionally afforded certain documents pursuant to evidentiary privileges in the civil discovery context, including materials which would be protected under the attorney-client privilege, the attorney work-product privilege, or the executive deliberative process privilege." Formaldehyde Institute v. Department of Health and Human Servs., 889 F.2d 1118, 1121 (D.C.Cir.1989) (internal quotation marks and citations omitted); see also United States v. Weber Aircraft Corp., 465 U.S. 792, 799, 104 S.Ct. 1488, 1492, 79 L.Ed.2d 814 (1984) (stating that "Exemption 5 simply incorporates civil discovery privileges").
The Justice Department here relies on the common law "deliberative process" or "executive" privilege as one of the privileges incorporated into Exemption 5. This ancient privilege is predicated on the recognition "that the quality of administrative decision-making would be seriously undermined if agencies were forced to operate in a fishbowl." Wolfe v. Department of Health and Human Servs., 839 F.2d 768, 773 (D.C.Cir.1988) (en banc). We have said that "the purpose of Exemption 5 is to encourage the 'frank discussion of legal and policy issues.' " Id. (quoting S.Rep. No. 813, 89th Cong., 1st Sess. 9 (1965)). But — and this is the government's problem — in order to qualify for the deliberative process privilege under Exemption 5, the government must demonstrate that the document is either inter-agency or intraagency in nature, and also that it is both predecisional and part of the agency's deliberative process. See id. at 774; see also Formaldehyde Institute, 889 F.2d at 1121.
The Department argues that the district court correctly decided that Exemption 5 covers materials sent from an Executive Branch agency to Congress. In other words, the government reads the word "inter-agency" to include inter-branch communications. The district court conceded that the government's interpretation does not comport with a "strict reading" of the language, but it thought a strict reading would frustrate the purpose of the statute. See 724 F.Supp. at 988. That is so, argues the government, because Congress exempted itself from FOIA, thereby protecting all of its internal deliberations. Therefore, it could not have intended that Executive Branch communications to Congress for the purpose of Congress' own internal deliberations be disclosable under FOIA.
It is an appealing argument. It may well be true that if Congress had thought about this question, the Exemption would have been drafted more broadly to include Executive Branch communications to Congress, such as the letter sought here. But Congress did not, and the words simply will not stretch to cover this situation, because Congress is simply not an agency.
Section 552(f) defines "agency" as follows:
For purposes of this section, the term "agency" as defined in section 551(1) of this title includes any executive department, military department, Government corporation, Government controlled corporation, or other establishment in the executive branch of the Government (including the Executive Office of the President), or any independent regulatory agency.
5 U.S.C. § 552(f). Section 551(1), in turn, defines "agency" for purposes of FOIA as "each authority of the Government of the United States, whether or not it is within or subject to review by another agency, but does not include . the Congress . [or] the courts of the United States." 5 U.S.C. § 551(1) (emphasis added). Accordingly, we have previously recognized that members of Congress are not within the definition of agency under FOIA. See Formaldehyde Institute, 889 F.2d at 1122. The argument from anomaly that the government makes and the district court accepted is just not adequate to sidestep this statutory language. See Weber Aircraft, 465 U.S. at 802, 104 S.Ct. at 1494 (noting that "compelling evidence of congressional intent . would be necessary to persuade us to look beyond the plain statutory language [of Exemption 5]"); see also Hallstrom v. Tillamook County, — U.S. —, 110 S.Ct. 304, 310, 107 L.Ed.2d 237 (1989) (stating that " 'absent a clearly expressed legislative intention to the contrary,' the words of the statute are conclusive") (quoting Consumer Product Safety Comm'n v. GTE Sylvania, Inc., 447 U.S. 102, 108, 100 S.Ct. 2051, 2056, 64 L.Ed.2d 766 (1980)).
To be sure, we did say in Ryan v. Department of Justice, 617 F.2d 781 (D.C.Cir.1980), that "Congress apparently did not intend 'inter-agency' and 'intra-agency' to be rigidly exclusive terms." Id. at 790. The government relies on Ryan, as did the district court. In Ryan, we held that questionnaires sent by the Justice Department to every Senator were intra -agency documents protected by Exemption 5 despite the fact that the materials physically left the Department (they were later returned by the Senators). The Department, in evaluating its own efforts to recommend more women and minorities to the federal bench, sought information from each Senator on how he or she selected potential nominees. We noted that in the course of internal deliberations an agency "often needs to rely on the opinions and recommendations of temporary consultants, as well as its own employees." Id. at 789. "Such consultations are an integral part of its [the agency's] deliberative process; to conduct this process in public view would inhibit frank discussion of policy matters and likely impair the quality of decisions." Id. at 789-90 (emphasis added). Therefore, as long as the documents are created for the purpose of aiding the agency's deliberative process, as were the questionnaires in Ryan, they will be deemed intra -agency documents even when created by non-agency personnel. See id. at 790.
Similarly, in Formaldehyde Institute, we determined that Exemption 5 applies even to an implicit consultation relationship between an agency and outsiders. See 889 F.2d at 1124-25. In that case, an agency employee, acting in his official capacity, submitted a scholarly article to a professional journal for possible publication. After consulting outside reviewers, the journal decided not to publish the article. We thought the journal's letter to the agency (with attached referee's comments) an intra-agency document because the agency had routinely used the journal's review process as part of the agency's own decision whether to publish and in what form. We reiterated that " '[w]hether the author [of the document subject to the FOIA request] is a regular agency employee or a temporary consultant is irrelevant; the pertinent element is the role, if any, that the document plays in the process of agency deliberations.' " Id. at 1122 (quoting CNA Financial Corp. v. Donovan, 830 F.2d 1132, 1161 (D.C.Cir.1987), cert. denied, 485 U.S. 977, 108 S.Ct. 1270, 99 L.Ed.2d 481 (1988)).
Ryan (and Formaldehyde), then, stand for the proposition that Exemption 5 permits an agency to protect the confidentiality of communications from outside the agency so long as those communications are part and parcel of the agency's deliberative process. As such, they remain intraagency documents. None of our cases have extended that notion, however, to the protection of deliberations of a non-agency either as an interpretation of "intra-agency" or "inter-agency." In the case at bar, the Department had unquestionably ended its consideration as to whether to prosecute, or in any other way proceed against, Representative St Germain before it sent the letter to Congress. For that reason, we do not think that the Department's letter to the House Ethics Committee can be withheld under Exemption 5.
III.
That brings us to the Department's alternative argument, that Exemption 7(D) justifies withholding of those parts of the letter that reflect information obtained from FBI witness interviews. Exemption 7(D) protects "records or information compiled for law enforcement purposes, but only to the extent that the production of such law enforcement records or information . could reasonably be expected to disclose the identity of a confidential source . and, in the case of a record or information compiled by criminal law enforcement authority in the course of a criminal investigation ., information furnished by a confidential source." 5 U.S.C. § 552(b)(7)(D). Unlike Exemption 5's deliberative process privilege, which depends on the factual content and purpose of the requested document, "the availability of Exemption 7 depends . upon whether the source was confidential." Shaw v. FBI, 749 F.2d 58, 61 (D.C.Cir.1984) (emphasis in original) (internal quotations and citation omitted); see also King v. Department of Justice, 830 F.2d 210, 235 n. 182 (D.C.Cir.1987). If the Department can demonstrate that the "information was 'provided in con fidence' at the time it was communicated to the FBI," Irons v. FBI, 880 F.2d 1446, 1448 (1st Cir.1989) (fin banc) (quoting Shaw, 749 F.2d at 61), the source will be deemed a confidential one, and both the identity of the source and the information he or she provided will be immune from FOIA disclosure.
As with the other FOIA exemptions, "the burden is on the agency to sustain its action." 5 U.S.C. § 552(a)(4)(B); see also Shaw, 749 F.2d at 61. But as we reiterated just recently in Schmerler v. FBI, 900 F.2d 333 (D.C.Cir.1990), "the law of this Circuit is that 'in the absence of evidence to the contrary, promises of confidentiality are inherently implicit when the FBI solicits information.' " Id. at 337 (quoting Keys v. Department of Justice, 830 F.2d 337, 345 (D.C.Cir.1987) (internal quotations omitted)). As long as the Department can show "that the information was solicited during the course of law enforcement investigations, the FBI raises a presumption that assurances were given" in exchange for the information. Id.
Dow Jones contends that it has rebutted the Schmerler presumption. Those individuals who provided the FBI with information — the allegedly confidential sources— merely described to the FBI matters which presumably occurred in public view. They apparently told the FBI whom Representative St Germain dined with and on what occasions. In the absence of any showing on the part of the government that these sources had some kind of personal or business relationship with the ex-Congressman, Dow Jones argues that there is no reason to believe that they wished confidentiality. We do not think that that proposition follows at all. We doubt that those who witness a congressman's public behavior— whether other congressmen, lobbyists, or restaurant employees — would typically appreciate being identified as the FBI's witnesses. Public behavior of the congressman is one thing; public identification of the witnesses is quite another. We think appellant's claim regarding all the witnesses is even weaker than that rejected in Schmerler.
In Schmerler, a Columbia University anthropology graduate student conducting research at an Indian reservation was sexually assaulted and murdered almost sixty years ago. The victim's nephew, in the course of writing a book about the event, sought disclosure of the FBI files covering the investigation. He particularly wanted the identities of certain individuals at Columbia University who provided character information about the victim. We were not persuaded by the argument that since the information the individuals provided was presumably favorable they needed not fear reprisals (if they were still alive), and that confidentiality was therefore not implicit in those interviews. We refused to be drawn into a sixty-year-old dispute over whether the witnesses would have objected to the public dissemination of their statements. To avoid that sort of difficult, ad hoc line drawing, we concluded that whether a source is confidential cannot turn on the substance of the information given. See Schmerler, 900 F.2d at 337-38; see also King, 830 F.2d at 233 ("[I]t is difficult, if not impossible, to anticipate all respects in which disclosure might damage reputations or lead to personal embarrassment and discomfort.") (internal quotations and citations omitted).
We readily admit that the presumption we applied in Keys, and especially in Schmerler, in practical terms comes close to an irrebuttable one. The requester will rarely, if ever, have absolutely solid evidence showing that the source of an FBI interview in a law enforcement investigation has manifested complete disregard for confidentiality. Of course, if the exact information given to the FBI has already become public, and the fact that the informant gave the same information to the FBI is also public, there would be no grounds to withhold. But short of these extraordinary circumstances, the "presumption" will govern. We believe, however, that in so interpreting FOIA we are following the Supreme Court's guidance in United States Dep't of Justice v. Reporter's Comm. for Freedom of the Press, 489 U.S. 749, 109 S.Ct. 1468, 103 L.Ed.2d 774 (1989). There, a requester sought information on an FBI rap sheet drawn from public records. The Supreme Court, recognizing that a case-by-case inquiry into the public-private balance under Exemption 7 as to repeated requests for rap sheet information would be a terrible burden on the courts and result in ad hoc — and therefore unprincipled — determinations, said that "categorical decisions may be appropriate and individual circumstances disregarded when a case fits into a genus in which the balance characteristically tips in one direction." Id. 109 S.Ct. at 1483. By applying such a strong presumption as to the confidentiality of FBI sources interviewed in law enforcement investigations, we are merely following the direction the Supreme Court gave us in Reporter's Committee. Since the FBI typically promises confidentiality and rarely — if ever— will a source not desire it, only the starkest and most conclusive evidence of non-confidentiality will rebut the presumption.
The district court issued its opinion before Schmerler and therefore distinguished between the sources, holding that the government had established confidentiality with respect to only the primary witness and the associate of the primary witness. In light of the presumption, however, we do not draw any distinctions among the witnesses. All of them were interviewed as part of the FBI's investigation into the question of whether Representative St Ger-main had committed a crime. As such, all the sources are presumed confidential under Exemption 7(D).
Accordingly, the district court's judgment is affirmed in part and reversed in part.
It is so ordered.
. Dow Jones had previously obtained the letter in redacted form because the Washington Post, in a separate proceeding, successfully obtained portions of the letter from the grand jury materials.
. We are unpersuaded by the Department's contention that our en banc opinion in Wolfe (and the legislative history we cited there) support a government-wide, inter-branch exemption because we referred to "efficient Government operation." See Wolfe, 839 F.2d at 773-74 (quoting S.Rep. No. 813, 89th Cong., 1st Sess. 9 (1965)) (emphasis added). In the context of the opinion, it is clear that the word "government" was referring to the Executive Branch. See id. at 773 (stating that the deliberative process privilege was an "executive" privilege and that it was intended to protect "the quality of administrative decision-making"); see also Sears, 421 U.S. at 150, 95 S.Ct. at 1516 (referring to Exemption 5 as "the Government's executive privilege").
. As the district court noted, the parties do not dispute that the information contained in the redacted portion of the letter was compiled for law enforcement purposes, by criminal law enforcement authority, and in the course of a criminal investigation. See 724 F.Supp. at 991. Consequently, the only Exemption 7(D) issue before us is whether the sources here are confidential.
. Dow Jones also presents the analytically imaginative argument that the confidentiality presumption portion of Schmerler was dicta — not binding on us — because the appellant there did not contest the government's reading of Keys. We disagree, however, with this expansive notion of dicta. But for the presumption, which Schmerler, in truth, strengthened over that employed in Keys, the case would have come out the other way; the government's actual evidence of confidentiality was rather thin. See Schmerler, 900 F.2d at 337.
. One can imagine, for instance, a source falsely describing publicly what he or she told the FBI privately.