 United States Court of Appeals
         FOR THE DISTRICT OF COLUMBIA CIRCUIT



Argued November 22, 2019           Decided December 20, 2019

                        No. 18-5123

                   RYAN NOAH SHAPIRO,
                       APPELLANT

                              v.

          UNITED STATES DEPARTMENT OF JUSTICE,
                       APPELLEE


        Appeal from the United States District Court
                for the District of Columbia
                    (No. 1:16-cv-01399)


     Jeffrey Light argued the cause and filed the briefs for
plaintiff-appellant.

     Brian J. Field, Assistant U.S. Attorney, argued the cause
for appellee. With him on the brief were Jessie K. Liu, U.S.
Attorney, and R. Craig Lawrence, Assistant U.S. Attorney.

    Before: GARLAND, Chief Judge, GRIFFITH, Circuit Judge,
and WILLIAMS, Senior Circuit Judge.

   Opinion for the Court filed by Senior Circuit Judge
WILLIAMS.
                               2

     WILLIAMS, Senior Circuit Judge: In 1982 the Federal
Bureau of Investigation’s then-Director William Webster
published an article broaching the subject of “mosaic theory”
and describing a “test” the FBI conducted called “Operation
Mosaic.” Webster reviewed the way in which “seemingly
innocuous information [released under the Freedom of
Information Act] can be combined with records released at a
different time or with the requester’s personal knowledge,”
leading to revelations about sensitive FBI sources or
investigations—just as the individual tiles in a mosaic may
combine to reveal a complex meaning. Joint Appendix (“J.A.”)
130–31. In support, the Director quoted one of our decisions,
Halperin v. CIA, 629 F.2d 144, 150 (D.C. Cir. 1980), where we
wrote: “[E]ach individual piece of intelligence information,
much like a piece of jigsaw puzzle, may aid in piecing together
other bits of information even when the individual piece is not
of obvious importance in itself.”

    Appellant Dr. Ryan Shapiro has sought to use FOIA, 5
U.S.C. § 552 et seq., to explore the FBI’s thoughts about and
possible uses of mosaic theory in its handling of FOIA cases.
Dr. Shapiro filed a series of FOIA requests on the subject,
asking among other things for files that responded to the search
terms “Operation Mosaic” and “mosaic study” in various FBI
databases. J.A. 147–48. And he asked for “all other records
constituting or referring to Operation Mosaic.” J.A. 148. Later,
he filed a FOIA request for records relating to his FOIA
requests.

    Unsatisfied with the agency’s productions, Dr. Shapiro
went to court, where he lost on summary judgment. In this
appeal, he challenges the FBI’s explanations that certain files
were not responsive to his request or were destroyed.

     Because this case comes to us at summary judgement, we
review the district court’s determination de novo. See Sussman
                                3

v. U.S. Marshals Serv., 494 F.3d 1106, 1111 (D.C. Cir. 2007).
We must draw all reasonable inferences in Dr. Shapiro’s favor
and can rule for the FBI only if there is no material issue of fact
in dispute. See Inst. for Justice v. IRS, 941 F.3d 567, 569 (D.C.
Cir. 2019). As the FBI did not sufficiently explain its
determinations, we reverse the district court’s contrary ruling,
vacate the decision in part and remand for further proceedings.

                              * * *

     We start with a set of issues arising out of the FBI’s
handling of a “search slip” that evidently served as an
intermediate step in the Bureau’s search for “mosaic study” in
its Automated Case Support database (“ACS”). A “Universal
Index” search in ACS yields information indexed in the
automated databases that preceded ACS itself. Per the FBI’s
affiant, the indices cover “a variety of subject matters to include
individuals, organizations, events, or other subjects of
investigative interest.” J.A. 37.

     The FBI provided the search slip in question, actually a
spreadsheet, in response to Dr. Shapiro’s FOIA request for
information about his FOIA requests. According to the FBI’s
affiant, search slips keep track of the “preliminary results of the
[agency’s] search,” and the FBI “routinely lists all potentially
responsive files on a search slip for administrative tracking
purposes.”

      In this case, the search slip identified 28 files as
“responsive” or “potential[ly]” responsive.         J.A. 104–05.
Evidently as a result of further examination, the FBI
reclassified the files, informing Dr. Shapiro that no records met
his request. In response to Dr. Shapiro’s complaint that the FBI
had withheld files indicated on the search slip as responsive,
the FBI supplied an affidavit explaining that on review the files
were found “either non-responsive because the files did not
                                4

relate to the specifics of [Dr. Shapiro’s] request or were legally
destroyed.” J.A. 181–82. As to 16 numbered files, the affidavit
specified which—whether they were non-responsive or
destroyed. As to certain files, whose numbers had been
redacted, the FBI response didn’t even disclose which of those
two categories the FBI believed applicable.

     (We pause to note that the FBI may not have needed to
release its search slip to Dr. Shapiro in the first place. FOIA’s
exemption 5 permits agencies to withhold “pre-decisional and
deliberative” materials. Nat’l Sec. Archive v. CIA, 752 F.3d
460, 463 (D.C. Cir. 2014). Exemption 5 might have applied to
the search slip in this case. See Assassination Archives &
Research Ctr. v. CIA, 781 F. Appx 11, 13 (D.C. Cir. 2019) (per
curiam) (unpublished). Nevertheless, the FBI gave Dr. Shapiro
the search slip, enabling him to marshal it as evidence.)

    In three respects, the FBI’s explanation doesn’t provide
enough information to permit ruling for the government on
summary judgement.

     First, the affidavit does not explain how the agency
concluded that the files preliminarily listed as responsive did
not relate to Dr. Shapiro’s request. (Dr. Shapiro makes no
claim as to the file listed on the search slip as only potentially
responsive. Reply Br. 15.) We recognize that the search slip
purported only to record a preliminary finding. And obviously
the law should not force an agency to jump through complex
hoops merely because a preliminary review seemed positive;
such a rule would likely incline an agency to take a rather
grudging view in its first screening. What’s more, in FOIA
cases, courts frequently rely on “reasonably detailed
affidavit[s]” to affirm the nature and adequacy of an agency’s
search. See DiBacco v. U.S. Army, 795 F.3d 178, 188 (D.C.
Cir. 2015) (citation and quotation omitted). And we give these
agency affidavits “a presumption of good faith.” SafeCard
                                5

Servs., Inc. v. SEC, 926 F.2d 1197, 1200 (D.C. Cir. 1991). But
where a record’s presence on a search slip arose from some sort
of “hit” in the FBI’s indexing system, and especially where the
search slip distinguished between responsive and potentially
responsive files, the FBI can obtain summary judgment (as to
files originally identified as “responsive”) only by offering
some non-conclusory justification for each ultimate
classification as non-responsive. Id. at 1201 (affidavit cannot
be “conclusory”).

     Second, the affidavit says nothing—at least nothing
clear—about the files whose numbers were redacted, though it
identifies each numbered file as either non-responsive or
destroyed. As a result, we have no idea whether those redacted
records—originally listed as responsive in the search slip—
were not responsive or had been destroyed (and which). This
leaves us with “positive indications of overlooked materials”
and “substantial doubt” about the adequacy of the
government’s search. See DiBacco, 795 F.3d at 188 (citation
and quotation omitted).

     Third, the affidavit does not explain why or how the FBI
knew that certain files had been destroyed. To be sure, “[i]f the
agency is no longer in possession of” files, it need not “take
further action in order to produce” them. SafeCard, 926 F.2d
at 1201. But affidavits must provide “adequate assurance that
the documents were in fact destroyed.” Id. at 1201; cf.
Weisberg v. DOJ, 627 F.2d 365, 369 (D.C. Cir. 1980) (holding
that a statement of belief that a record had been destroyed did
not constitute a sufficient explanation). True enough, the FBI’s
affidavit alludes to its practice of handling record retention and
disposal “under supervision of the National Archives and
Records Administration,” J.A. 182 n.3, perhaps implying that
these were destroyed pursuant to regular retention schedules.
Cf. Agolli v. DOJ, 2016 WL 6238495, at *1 (D.C. Cir. 2016)
(per curiam) (unpublished) (affirming agency’s production
                                6

when files had been “destroyed in accordance with its retention
schedules”). But the affidavit must set forth not just an
agency’s conclusion that it no longer possesses a document but
also some underlying fact or facts to show the document’s
likely fate. At oral argument, government counsel suggested
that the agency recorded the files’ destruction in a log. If
presented in an affidavit, such an explanation would suffice.

    On remand, the district court should permit the FBI to
submit further evidence to supplement these three deficiencies
and to file a renewed motion for summary judgment.

                             * * *

     The FBI also ran a search for the term “Operation Mosaic”
in its Electronic Case Filing System (“ECF”) and Sentinel
databases. Unlike the ACS index, an “ECF text search returns
‘hits’ for search terms located within all electronically uploaded
documents.” J.A. 178 (emphasis added). Sentinel likewise
searches a document’s full text, as well as some additional
information. In everyday terms, searching ACS seems akin to
opening a book to a specific index entry and finding the page
numbers which the indexer identified as relevant. An ECF or
Sentinel text search, by contrast, combs through the entire
(metaphorical) book to identify each instance in which the word
appears in the text, as one might with an e-book.

     The ECF and Sentinel searches for Operation Mosaic
returned five hits, all of which the FBI concluded did not
respond to Dr. Shapiro’s request. According to the FBI, two of
the files concerned “a Human Trafficking Operation, and the
term ‘Mosaic’ was located in the business name that provided
services to the victims.” J.A. 289. Dr. Shapiro disclaims any
interest in these files. See Appellant’s Br. 35–36 (“Although
arguably within the scope of Dr. Shapiro’s broad requests, he
                                 7

does not challenge the FBI’s non-responsiveness determination
as to these two records.”).

     For the other three files, the FBI’s affiant simply stated that
the files “consisted of counterintelligence and organized crime
information.” As to these, Dr. Shapiro offers two arguments
for why he should receive them. He first points to the argument
in Director Webster’s own article that the mosaic effect’s
impact was “perhaps greatest in our organized crime program
and in our foreign counterintelligence program.” J.A. 117.
Thus, he says, the FBI needs to provide more explanation for
why those files’ references to the same topics did not involve
Director Webster’s Operation Mosaic. We agree, especially
considering the FBI’s having explained the use of “mosaic” in
the two withheld records relating to human trafficking.

     Because of our decision to remand for a fuller explanation,
we need not address Dr. Shapiro’s second argument: These
three files—even if they reference a different Operation
Mosaic—fell within the literal terms of his request directly, as
they reference the term “Operation Mosaic.” Though Dr.
Shapiro had framed his request by reference to the mosaic
effect identified by Director Webster, he had added that his
inclusion of that framing was “to enable the FBI to locate the
requested records [and] not intended to limit the scope of my
request.” Reply Br. 24; J.A. 157. At oral argument counsel
explained that Dr. Shapiro sought these records “because of [a]
concern that the FBI would make erroneous determinations
about what is of interest to him and what is not,” Oral Argument
at 47:14, a plausible rationale for his wishing to see the files. If
the FBI offers a fuller explanation on remand, he may be
satisfied, and neither the district court nor we will need to
address the legal questions his second argument raises. Cf.
LaCedra v. Exec. Office for U.S. Att’ys., 317 F.3d 345, 348
(D.C. Cir. 2003).
                                8

                             * * *

     In his briefs, Dr. Shapiro argued that pursuant to another
request on appeal here the FBI must conduct an ECF full text
search of “FBI Research Matters” files (known as “94” files)
for ones referring to the Freedom of Information Act and/or the
Privacy Act. See Appellant Br. 11. Before oral argument, the
government agreed to conduct that search. We thus agree to
the parties’ joint request that we vacate the district court’s
opinion on this point and remand the matter, preserving Dr.
Shapiro’s ability to challenge the adequacy of the FBI’s search.

                             * * *

     The decision of the district court is reversed with respect
to the files identified as “responsive” in the search slip and the
three ACS/Sentinel files, vacated with respect to the 94 files,
and remanded for further proceedings not inconsistent with this
opinion.

                                                     So ordered.
