 United States Court of Appeals
         FOR THE DISTRICT OF COLUMBIA CIRCUIT



Argued September 11, 2013             Decided March 14, 2014

                        No. 12-5183

     PEOPLE FOR THE ETHICAL TREATMENT OF ANIMALS,
                      APPELLANT

                             v.

NATIONAL INSTITUTES OF HEALTH, DEPARTMENT OF HEALTH
                AND HUMAN SERVICES,
                      APPELLEE


        Appeal from the United States District Court
                for the District of Columbia
                    (No. 1:10-cv-01818)



    Eric R. Glitzenstein argued the cause for appellant. With
him on the briefs were Katherine Anne Meyer and Jessica Almy.


     Marina Utgoff Braswell, Assistant U.S. Attorney, argued
the cause for appellee. With her on the brief were Ronald C.
Machen Jr., U.S. Attorney, and R. Craig Lawrence, Assistant
U.S. Attorney.

    Before: HENDERSON, GRIFFITH and SRINIVASAN, Circuit
Judges.
                                2

    SRINIVASAN, Circuit Judge: This case involves two
Freedom of Information Act (FOIA) requests submitted by
People for the Ethical Treatment of Animals (PETA) to the
National Institutes of Health (NIH). PETA requested records
concerning NIH investigations of animal abuse at a university
research lab, and specifically sought documents related to any
investigations into complaints filed against three identified
researchers. NIH issued Glomar responses, meaning that the
agency refused to confirm or deny the existence of responsive
documents on the ground that acknowledging their existence
would itself undercut privacy interests protected by FOIA.

     PETA challenged NIH’s Glomar responses in district court.
The district court determined that any NIH acknowledgment of
the existence of responsive records would reveal that the agency
had investigated the three researchers. The court therefore
upheld NIH’s Glomar responses under FOIA Exemption 7(C),
which permits withholding law enforcement information or
records if disclosure could entail an unwarranted invasion of
personal privacy.

     We affirm the validity of NIH’s Glomar responses as to
any documents that would reveal whether NIH had investigated
the three researchers. But we understand PETA’s request to
encompass additional types of documents that, insofar as they
may exist, would not disclose any investigations of the three
researchers. We therefore vacate in part the district court’s grant
of summary judgment to NIH.
                              3

                              I.

                              A.

     NIH, an agency within the Department of Health and
Human Services, provides federal funding for medical research,
including research involving animals. NIH grant recipients
must adhere to certain policies concerning the humane treatment
of laboratory animals. The NIH Office of Laboratory Animal
Welfare (OLAW) investigates allegations that grant recipients
have violated NIH policies. Universities receiving NIH funding
must establish an Institutional Animal Care and Use Committee,
which bears responsibility for monitoring compliance with NIH
guidelines and reporting any violations to OLAW.

    PETA is a non-profit organization that advocates for
animal rights. Among its activities, PETA investigates the
abuse of animals in research laboratories. This case concerns
PETA’s efforts to investigate the treatment of laboratory
animals at the Scott-Ritchey Research Center at Auburn
University, a state university in Alabama that receives NIH
funding for animal research.

     PETA reports that, in early 2005, it placed an undercover
investigator in one of Auburn’s research laboratories. Over an
eight-month period, the investigator allegedly documented
numerous violations of the Animal Welfare Act as well as the
misappropriation of NIH funds. On the basis of that
information, PETA assembled a written complaint. The
complaint names researchers who also are the subjects of
PETA’s FOIA requests at issue here.

     PETA states that it sent its complaint to NIH, but it is
unclear from the record whether the agency received it. PETA
also filed its complaint with the United States Department of
                               4

Agriculture (USDA). In response to a subsequent FOIA
request, USDA released the complaint in largely unredacted
form. USDA also released an investigatory report that had
concluded that the complaint was “partially valid.”

                              B.

     PETA filed three requests under FOIA with NIH seeking
records related to Auburn University. First, on February 28,
2006, PETA filed a request “for copies of all OLAW files
concerning Auburn University.” NIH identified several
hundred pages of responsive documents, but withheld or
redacted most of them. PETA’s first FOIA request is not at
issue in this appeal.

    On July 25, 2007, PETA filed a second FOIA request with
NIH, framed as follows:

       Pursuant to the federal Freedom of Information
       Act, 5 U.S.C. § 552, People for the Ethical
       Treatment of Animals (PETA) requests copies of
       all official investigative reports, preliminary
       notes, testimonies, memos, meeting minutes,
       phone conversations, emails and other materials
       related to all National Institutes of Health (NIH)
       investigations into complaints filed in 2005-
       present regarding [three specifically named NIH
       grant recipients] at Auburn University’s Scott-
       Ritchey Research Center in Auburn, AL.

NIH issued a Glomar response, refusing to confirm or deny the
existence of any responsive documents. NIH stated that any
such records would be exempt from disclosure under FOIA
Exemption 6, 5 U.S.C. § 552(b)(6), which protects against
clearly unwarranted invasions of personal privacy.
                               5

     On May 20, 2008, PETA sought certain documents from
Auburn University pursuant to Alabama’s Open Records Act.
In response, Auburn’s general counsel informed PETA that
PETA’s activities had “resulted in an investigation by NIH.”
The general counsel explained, however, that the university was
unable to disclose any further information because the
investigation was ongoing and the university had entered into a
confidentiality agreement with NIH.

      On August 21, 2008, PETA sent a third FOIA request to
NIH, this time seeking “[c]opies of any signed confidentiality
agreement between Auburn University and NIH relating to
materials and information with regard to an investigation into
the research of [a specifically named NIH grant recipient] and
colleagues.” The request named one of the same researchers
who had been named in PETA’s second request. NIH issued
another Glomar response, again invoking FOIA Exemption 6.
PETA filed an administrative appeal concerning its second and
third requests. The Department of Health and Human Services,
NIH’s parent organization, issued a final decision affirming the
agency’s Glomar responses under Exemptions 6 and 7(C).

     PETA then initiated the present action in the district court
challenging NIH’s Glomar responses to the second and third
requests. The district court granted summary judgment to NIH.
The court upheld the responses under FOIA Exemption 7(C), 5
U.S.C. § 552(b)(7)(C), which exempts from disclosure law
enforcement records and information whose release could
constitute an unwarranted invasion of personal privacy. PETA
v. NIH, 853 F. Supp. 2d 146, 154-59 (D.D.C. 2012). The court
determined that acknowledging the existence of documents
responding to PETA’s requests would confirm that NIH had
investigated the three named researchers. Id. at 155. Such a
confirmation, the court reasoned, would “go[] to the heart of the
privacy interest that Exemption 7(C) was designed to protect.”
                                6

Id. Concluding that any public interest in disclosure failed to
outweigh the privacy interests at stake, the district court upheld
NIH’s Glomar responses. Id. at 159. PETA now appeals,
challenging the validity of NIH’s Glomar responses to the
second and third requests.

                               II.

      The Freedom of Information Act “implement[s] a general
philosophy of full agency disclosure.” U.S. Dep’t of Justice v.
Reporters Comm. for Freedom of the Press, 489 U.S. 749, 754
(1989) (internal quotation marks omitted). The statute “requires
every federal agency, upon request, to make ‘promptly available
to any person’ any ‘records’ so long as the request ‘reasonably
describes such records.’” Assassination Archives & Research
Ctr. v. CIA, 334 F.3d 55, 57 (D.C. Cir. 2003) (quoting 5 U.S.C.
§ 552(a)(3)). Agencies have “a duty to construe a FOIA request
liberally.” Nation Magazine v. U.S. Customs Serv., 71 F.3d 885,
890 (D.C. Cir. 1995). An agency can withhold or redact
documents only if the information falls within one of nine
statutory exemptions. See 5 U.S.C. § 552(b)(1)-(9). The agency
bears the burden of establishing that an exemption applies.
Reporters Comm., 489 U.S. at 755. An agency ordinarily must
search for any documents responsive to the request, and must
“disclose all reasonably segregable, nonexempt portions of the
requested record(s).” Assassination Archives, 334 F.3d at 58
(citing 5 U.S.C. § 552(b)).

      In certain cases, merely acknowledging the existence of
responsive records would itself “cause harm cognizable under
[a] FOIA exception.” Wolf v. CIA, 473 F.3d 370, 374 (D.C. Cir.
2007) (quoting Gardels v. CIA, 689 F.2d 1100, 1103 (D.C. Cir.
1982)) (internal quotation mark omitted). In that event, an
agency can issue a Glomar response, refusing to confirm or deny
its possession of responsive documents. The Glomar response
                                7

takes its name from the CIA’s refusal to confirm or deny the
existence of records about “the Hughes Glomar Explorer, a ship
used in a classified [CIA] project ‘to raise a sunken Soviet
submarine from the floor of the Pacific Ocean to recover the
missiles, codes, and communications equipment onboard for
analysis by United States military and intelligence experts.’”
Roth v. U.S. Dep’t of Justice, 642 F.3d 1161, 1171 (D.C. Cir.
2011) (quoting Phillippi v. CIA, 655 F.2d 1325, 1327 (D.C. Cir.
1981)). A Glomar response is valid “if the fact of the existence
or nonexistence of agency records falls within a FOIA
exemption.” Wolf, 473 F.3d at 374.

     Courts can grant summary judgment upholding a Glomar
response based on agency affidavits explaining the basis for the
response. Affidavits must contain “reasonable specificity of
detail rather than merely conclusory statements” and cannot be
“called into question by contradictory evidence in the record.”
Elec. Privacy Info. Ctr. v. Nat’l Sec. Agency, 678 F.3d 926, 931
(D.C. Cir. 2012) (internal quotation marks omitted). Contrary
to PETA’s assertions, to the extent the circumstances justify a
Glomar response, the agency need not conduct any search for
responsive documents or perform any analysis to identify
segregable portions of such documents. See Wolf, 473 F.3d at
374 n.4; Elec. Privacy Info. Ctr., 678 F.3d at 934.

      In this case, NIH justifies its Glomar responses under
FOIA Exemptions 6 and 7(C). Exemption 6 protects “personnel
and medical files and similar files the disclosure of which would
constitute a clearly unwarranted invasion of personal privacy.”
5 U.S.C. § 552(b)(6). Exemption 7(C) 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 constitute an
unwarranted invasion of personal privacy.”              5 U.S.C.
§ 552(b)(7)(C). PETA does not dispute that any responsive
                                8

documents would constitute “records or information compiled
for law enforcement purposes” for purposes of Exemption 7(C).
Because “Exemption 7(C)’s privacy language is broader than the
comparable language in Exemption 6,” Reporters Comm., 489
U.S. at 756, we confine our analysis to Exemption 7(C).

                               III.

      We review de novo the district court’s conclusion that
Exemption 7(C) justifies NIH’s Glomar responses to PETA’s
second and third FOIA requests. That exemption supports a
Glomar response if acknowledgment of responsive documents
“could reasonably be expected to constitute an unwarranted
invasion of personal privacy.” 5 U.S.C. § 552(b)(7)(C). To
answer that question, we “weigh the public interest in the release
of information against the privacy interest in nondisclosure.”
Schrecker v. U.S. Dep’t of Justice, 349 F.3d 657, 661 (D.C. Cir.
2003). We consider PETA’s second and third FOIA requests in
turn.

                                A.

      PETA’s second FOIA request encompasses “materials
related to all [NIH] investigations into complaints . . . regarding
[the three named researchers] at Auburn University’s Scott-
Ritchey Research Center.” We conclude that a Glomar response
is warranted for the heartland of responsive documents, but we
hold that NIH’s across-the-board Glomar response is unjustified
because certain types of responsive documents would fall
outside of Exemption 7(C).

                                1.

    PETA’s second request by its terms and at its
core seeks disclosure of records that would confirm that NIH
                                9

had investigated the three researchers. We agree with the
district court that Exemption 7(C) justifies a Glomar response
for any such documents.

     Courts have repeatedly recognized the “substantial”
privacy interest held by “the targets of law-enforcement
investigations . . . in ensuring that their relationship to the
investigations remains secret.” Roth, 642 F.3d at 1174 (internal
quotation marks omitted). In Jefferson v. Department of Justice,
284 F.3d 172, 180 (D.C. Cir. 2002), for instance, we emphasized
an Assistant U.S. Attorney’s strong privacy interest in avoiding
the disclosure of any investigation of misconduct. See also
Schrecker, 349 F.3d at 666 (“We have long recognized . . . that
‘the mention of an individual’s name in a law enforcement file
will engender comment and speculation and carries a
stigmatizing connotation.’” (quoting Fitzgibbon v. CIA, 911
F.2d 755, 767 (D.C. Cir. 1990))). The same concerns exist in
the context of non-criminal investigations, including
investigations of federal research-grant recipients.           See
McCutchen v. U.S. Dep’t of Health & Human Servs., 30 F.3d
183, 187 (D.C. Cir. 1994) (noting that allegations of
“plagiarism, fabrication of research results, and similar breaches
of academic integrity . . . carry a stigma and can damage a
career.”). Here, as the district court observed, acknowledging an
NIH investigation of any of the named researchers would “go[]
to the heart of the privacy interest that Exemption 7(C) was
designed to protect.” PETA, 853 F. Supp. 2d at 155. Indeed,
“[t]here can be no clearer example of an unwarranted invasion
of personal privacy than to release to the public that another
individual was the subject of [a law enforcement] investigation.”
Fund for Constitutional Gov’t v. Nat’l Archives & Records
Serv., 656 F.2d 856, 864 (D.C. Cir. 1981) (quoting Baez v. Dep’t
of Justice, 647 F.2d 1328, 1338 (D.C. Cir. 1980)).
                                10

      PETA considers the privacy interest to be materially
diminished in this case for two reasons, neither of which is
persuasive. First, PETA observes that, because its request
names three individuals, an acknowledgment by NIH of
responsive documents would stop short of identifying which
specific one (or ones) of the three researchers had been
investigated. But even if the privacy interest may be lessened to
a degree when the affected individual is identified as among
three persons of whom one (or more) was the subject of an
investigation as compared with a situation in which a single
individual is revealed to have been the subject of an
investigation there is still a substantial privacy interest at stake
in the former circumstance. Official acknowledgment that there
was an NIH investigation of at least one and quite possibly all
three of the identified researchers would “engender comment
and speculation and carr[y] a stigmatizing connotation.”
Fitzgibbon, 911 F.2d at 767.

      Second, PETA notes that other entities, including USDA
and Auburn, have publicly acknowledged complaints and
investigations involving the named researchers. But “the fact
that an event is not wholly private does not mean that an
individual has no interest in limiting disclosure or dissemination
of the information.” Reporters Comm., 489 U.S. at 770 (internal
quotation marks omitted). Here, notwithstanding other entities’
acknowledgment of investigations, NIH’s own official
acknowledgment that it had investigated the named researchers
would carry an added and material stigma. That conclusion is
bolstered by Frugone v. CIA, 169 F.3d 772, 774 (D.C. Cir.
1999), and Moore v. CIA, 666 F.3d 1330, 1333 n.4 (D.C. Cir.
2011). In both cases, we upheld CIA Glomar responses even
though other agencies had previously disclosed responsive
information. Although Frugone and Moore did not specifically
involve Exemption 7(C), they rest on the special significance of
official acknowledgment by the agency itself. That significance
                               11

tips the balance here towards the researchers’ privacy interest,
despite the third-party disclosures.

      In light of the substantial privacy interests at stake,
Exemption 7(C) authorizes a Glomar response unless the public
interest in disclosure is strong enough to justify the privacy
invasion. PETA “must show that the public interest sought to be
advanced is a significant one, an interest more specific than
having the information for its own sake,” and also that “the
information is likely to advance that interest.” Nat’l Archives &
Records Admin. v. Favish, 541 U.S. 157, 172 (2004). In
addition, the only cognizable public interest under FOIA is “the
citizens’ right to be informed about what their government is up
to.” Reporters Comm., 489 U.S. at 773 (internal quotation
marks omitted). There is thus no cognizable FOIA interest in
examining whether private individuals conduct animal research
in an appropriate manner: that interest does not speak directly
to governmental activity. See id.

      On the other hand, there is a cognizable public interest in
learning how NIH handles complaints concerning animal abuse
and misappropriation of federal research funds. Responsive
documents might illuminate various aspects of NIH’s
operations, including how the agency decides whether to
investigate complaints and how it conducts investigations.
PETA asserts that it seeks to uncover precisely that sort of
information. Any such information would advance the public
interest in “shed[ding] light on an agency’s performance of its
statutory duties.” Id.; see also Nation Magazine, 71 F.3d at 894-
95 (“[T]he mere fact that records pertain to an individual’s
activities does not necessarily qualify them for exemption. Such
records may still be cloaked with the public interest if the
information would shed light on agency action.”).
                               12

     In the circumstances of this case, however, we conclude
that the public interest in understanding the agency’s
investigatory processes fails to outweigh the researchers’
substantial interest in nondisclosure. We have consistently held
that Exemption 7(C) authorizes Glomar responses to
comparable FOIA requests seeking information about particular
individuals. For example, in Jefferson, we considered a request
seeking investigatory records concerning a specific Assistant
U.S. Attorney. 284 F.3d at 175. We not only upheld the
agency’s Glomar response as to that part of the request, but we
found the “result virtually compelled by” our decisions. Id. at
179 (citing Kimberlin v. Dep’t of Justice, 139 F.3d 944, 948
(D.C. Cir. 1998)); see also Beck v. Dep’t of Justice, 997 F.2d
1489, 1493-94 (D.C. Cir. 1993) (upholding Glomar response to
request for any complaints or other investigatory files
concerning two named Drug Enforcement Administration
agents); Dunkelberger v. Dep’t of Justice, 906 F.2d 779, 782
(D.C. Cir. 1990) (upholding Glomar response to request for a
specific FBI agent’s disciplinary records). In each of those
cases, the FOIA request implicated the public interest in
shedding light on agency investigatory procedures the same
interest PETA asserts here. Yet we have consistently found that
interest, without more, insufficient to justify disclosure when
balanced against the substantial privacy interests weighing
against revealing the targets of a law enforcement investigation.
We see no reason to reach a different conclusion here.

       That result is fully consistent with our decision in Nation
Magazine, 71 F.3d at 892-96, on which PETA substantially
relies. There, the plaintiff magazine filed a FOIA request with
the U.S. Customs Service for any documents pertaining to then-
presidential candidate H. Ross Perot. Id. at 888. Perot had
publicly stated that he had offered to assist the Customs Service
in its drug interdiction efforts. Id. at 896. The magazine wished
to determine the extent to which the agency had accepted Perot’s
                               13

offers and privatized some of its operations. Id. at 895-96. We
rejected the Customs Service’s Glomar response. Id. at 893.
Noting the cognizable public interest in learning how the
“agency responded to [Perot’s] overtures,” we held that the
agency’s categorical policy of issuing a Glomar response for
any request naming an individual was too broad. Id. at 895.

     Here, the privacy interest is considerably stronger than in
Nation Magazine. Whereas Nation Magazine concerned Perot’s
efforts to assist the Customs Service, PETA’s request relates to
investigations of the three named researchers. As we observed
in Nation Magazine, “records discussing offers of assistance
may implicate a less substantial privacy interest than any records
associating Perot with criminal activity.”           Id. at 894.
Additionally, Perot himself had publicly disclosed some of his
communications with the agency. Id. at 896. Here, by contrast,
neither the named researchers nor NIH have made any public
disclosures. The material difference in the character of the
privacy interests at stake in the two cases calls for a different
conclusion here than in Nation Magazine.

     For these reasons, we hold that NIH may issue a Glomar
response as to any documents that would confirm the existence
of an investigation into the three named researchers.

                                2.

     If PETA’s second request were confined to records
revealing the existence of an investigation of the three
researchers, NIH’s blanket Glomar response would be fully
warranted and our analysis of that request would be at an end.
The district court construed the second request in precisely that
fashion. See PETA, 853 F. Supp. 2d at 155 (“There is no
question that a response from the agency acknowledging the
existence of the records . . . would confirm that those three
                               14

individuals were being or had been investigated.”). That
interpretation is understandable. PETA framed the request to
encompass “materials related to all [NIH] investigations into
complaints . . . regarding” the three researchers. So framed, the
request is amenable to an understanding under which it seeks
only documents connected to an ongoing or past investigation of
the three individuals, the disclosure of which would necessarily
reveal the existence of such an investigation.

     In view of the duty to construe FOIA requests liberally,
however, see Nation Magazine, 71 F.3d at 890, we understand
PETA’s second request more broadly to reach two additional
categories of documents, neither of which would necessarily
reveal an investigation of the researchers. First, NIH could
possess documents showing that the agency had received
complaints about the researchers that it elected not to
investigate. PETA’s request includes any records “related to”
NIH investigations not just records of actual investigations.
See id. (emphasizing the broadening effect of the phrase
“pertaining to”). The request therefore encompasses the stages
antecedent to an investigation, including documents explaining
why an investigation did or did not occur. PETA, for example,
hypothesizes an internal NIH memorandum acknowledging the
receipt of PETA’s complaint but stating that the agency would
decline to investigate it due to a lack of resources.

      PETA argues that Exemption 7(C) does not justify a
Glomar response for that type of records, reasoning that there
could be no privacy interest in confirming the absence of an
investigation. We conclude, however, that a Glomar response
is valid for such records. If NIH were required to acknowledge
responsive documents in instances where there was no
investigation but were permitted to give a Glomar response in
cases where there had been one, it would become apparent that
a Glomar response really meant that an investigation had
                               15

occurred. The agency must be permitted to issue a Glomar
response in both situations to maintain the uncertainty essential
to Glomar’s efficacy. We therefore hold that NIH can issue a
Glomar response with regard to documents showing that the
agency received complaints about the researchers but declined
to conduct an investigation in response.

      There also exists a second category of responsive
documents beyond those that would necessarily reveal an
investigation of the three researchers: documents showing that
NIH responded to complaints about the three researchers by
conducting an investigation that did not target the researchers
themselves. Although PETA’s request presupposes a complaint
filed against the named researchers, the request, broadly
construed, encompasses documents relating to any ensuing
investigation. So, for example, if NIH responded to a complaint
against the researchers by investigating whether Auburn’s
Institutional Animal Care and Use Committee was performing
proper oversight, any documents related to that investigation
would fall within the terms of the second request.

     We conclude that Exemption 7(C) does not justify a
Glomar response for that category of responsive documents.
Because there would be no disclosure of the existence of an
investigation of the named researchers, the privacy interest at
stake would be diminished. On the other side of the balance, the
circumstances would directly implicate the cognizable public
interest in shedding light on NIH’s investigatory processes. See
Reporters Comm., 489 U.S. at 773. Acknowledging an
investigation that did not target the researchers would serve to
advance that public interest without unduly compromising the
researchers’ privacy interests. We therefore hold that disclosure
of documents of that type could not “reasonably be expected to
constitute an unwarranted invasion of personal privacy” for
                               16

purposes of Exemption 7(C), 5 U.S.C. § 552(b)(7)(C); cf. Nation
Magazine, 71 F.3d at 893-95.

     Because there exists a category of responsive documents
for which a Glomar response would be unwarranted, NIH’s
assertion of a blanket Glomar response to the second request
cannot be sustained. We thus vacate the district court’s grant of
summary judgment to NIH as to PETA’s second request. On
remand, NIH must search for any documents showing that, in
response to complaints filed against the named researchers, the
agency conducted an investigation other than one targeting the
researchers. But NIH still may issue a narrowed Glomar
response for any documents revealing whether the agency
investigated the researchers themselves. See Am. Civil Liberties
Union v. CIA, 710 F.3d 422, 434 & n.13 (D.C. Cir. 2013)
(contemplating assertion of a “more limited Glomar response”
on remand); Nation Magazine, 71 F.3d at 895-96 (same).

                               B.

      PETA’s third FOIA request seeks copies of any
confidentiality agreement between Auburn University and NIH
“relating to materials and information with regard to an
investigation into the research of [a named researcher] and
colleagues.” NIH’s acknowledgment of responsive documents
would confirm that the agency had investigated the researchers,
implicating substantial privacy interests at the core of
Exemption 7(C). Although there may be a cognizable public
interest in understanding how NIH uses confidentiality
agreements when conducting investigations, that interest alone
cannot overcome the substantial privacy interests at stake. See
Part III.A.1, supra. PETA of course remains free to formulate
a new FOIA request pertaining to NIH’s use of confidentiality
agreements without tying the request to investigations of
specific researchers.
                             17


                           * * *

     We vacate the district court’s grant of summary judgment
to NIH in connection with PETA’s second FOIA request and
remand for proceedings consistent with this opinion. We affirm
the grant of summary judgment to NIH as to PETA’s third FOIA
request.
