Appellant Alvie James Hale (“Hale”) appeals a district court order dated January 17, 1995 granting summary judgment in favor of the United States on Hale’s claims that the United States improperly withheld certain documents pursuant to 5 U.S.C. § 552(b)(7)(D) of the Freedom of Information Act (“FOIA”). The district court’s order was a final order which disposed of all claims with respect to all parties. The district court had jurisdiction pursuant to 5 U.S.C. § 552(a)(4)(B) of the FOIA. Hale filed a notice of appeal on February 10,1995, within sixty days of the district court’s order. Fed. R.App. P. 4(a)(1). We exercise jurisdiction pursuant to 28 U.S.C. § 1291 and remand for further proceedings consistent with this opinion.
I.
In 1983, Hale was convicted in the United States District Court for the Western District of Oklahoma under the Hobbs Act, 18 U.S.C. § 1951, for his actions in connection with the kidnaping and murder of William Jeffrey Perry.
Hale v. United States Dep’t of Justice,
In support of a collateral attack on his death sentence, Hale filed a FOIA request with the United States Department of Justice (“DOJ”) and the Federal Bureau of Investigation (“FBI”) in 1989 seeking the release of all information regarding the kidnaping and murder of William Perry. Id. at 896-97. The FBI withheld certain information from disclosure, claiming that the information was exempt from mandatory disclosure under several FOIA exemptions. Hale then sought injunctive relief against the government under 5 U.S.C. § 552(a)(4)(B) in the United States District Court for the Western District of Oklahoma. Id. at 897. After an in camera inspection of the documents in dispute, the district court upheld all claims of exemption and granted the United States’ motion for summary judgment on the grounds that the requested documents constituted information exempted from the FOIA pursuant to 5 U.S.C. §§ 552(b)(2), (b)(7)(C), (b)(7)(D), and (b)(7)(E). Id. at 897-98.
We affirmed the district court’s ruling in
Hale I.
Hale then filed a petition for writ of certiorari to the United States Supreme Court. In a short order dated June 28,1993, the Supreme Court granted certiorari, vacated our judgment in
Hale I,
and remanded the case to this court for further consideration in light of
United States Dep’t of Justice v. Landano,
On remand, we applied
Landano
to “modify the Tenth Circuit rule concerning Exemption 7(D) to require a source-by-source determination of the expectations of confidentiality.”
Hale v. United States Dep’t of Justice,
On remand from this court the FBI provided Hale and the district court with a new
Vaughn
affidavit,
see Vaughn v. Rosen,
II.
“[W]here the district court has granted summary judgment in favor of the government agency, we must review
de novo
the district court’s legal conclusions that the requested materials are covered by the relevant FOIA exemptions.”
Anderson v. Dep’t of Health and Human Servs.,
Exemption 7(D) permits the United States to withhold
records or information compiled for law enforcement purposes, but only to the extent that the production of such [material] could reasonably be expected to disclose the identity of a confidential source, ... and, in the ease 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). We have stated that “in order to invoke Exemption 7(D), the government must prove (1) that sources of
*1030
information are confidential and (2) that the information was acquired under an express assurance of confidentiality or that the circumstances were such that an assurance of confidentiality could be inferred.”
Hale I,
The Supreme Court in
Landano
held that the government is not entitled to a general presumption that sources supplying information to the FBI in the course of a criminal investigation are confidential sources within the meaning of Exemption 7(D).
Landano,
An agreement of confidentiality may be either express or implied. Express agreements are fairly straightforward and merely require the courts to determine, as a matter of fact, whether an express agreement of confidentiality had been entered into between the government and the source. We have reviewed those documents where the government has claimed an express agreement of confidentiality by designating withheld material with the Code (b)(7)(D)-7, and we affirm the district court’s holding that materials deleted under Code (b)(7)(D)7 were properly withheld to protect a confidential source.
See Rosenfeld v. United States Dep’t. of Justice,
Turning then to implied confidentiality, we are mindful that an inference of implied confidentiality should be evaluated on a case-by-case basis.
See Landano,
When relying on an inference of confidentiality, the government’s
Vaughn
index and affidavits, as well as the district court’s findings, should provide sufficient detail on a source-by-source basis to support an
*1031
assertion of implied confidentiality.
5
See Church of Scientology Int’l v. United States Dep’t of Justice,
When reviewing the “nature of the crime” to see if it supports an inference of confidentiality, we must be careful to follow the admonition in
Landano
not to east the net so widely as to give rise to an inference of confidentiality in all cases. All crime, of course, has the potential to be intimidating and to engender anxiety in those who testify about it. However, in the absence of an express agreement of confidentiality, the “nature of the crime” will ordinarily support an inference of confidentiality only when there are discrete aspects of the crime that make it particularly likely that a source reasonably would fear reprisal. Examples include (1) a gang-related crime of violence,
Landano,
Here, we have a violent crime involving kidnaping and murder. Further, it took place in a small Oklahoma town where apparently most everyone knew everyone else, and thus the interviewees would likely be known to any involved individuals. In addition, the nature of the crime was such that at the time of the interviews, it could not be known whether the crime was the act of a single individual or the concerted act of several individuals. On the other hand, there was no allegation by the government nor evidence of a public perception at the time of the interviews that this crime involved an organization such as a gang or extremist group with a persistent existence and propensity for violence. Nor is there any evidence that there were threats of retaliations issued against actual or potential sources. The crime was a single, discrete crime with an apparent economic motive. Thus, considerations related to the nature of the crime cut in both directions as to the likelihood that the inter *1032 viewees expected anonymity when talking to law enforcement personnel.
With respect to the source’s relation to the crime, we ask whether there is something unique to a particular source that would reasonably make that source feel particularly at risk of retribution for providing information to the FBI over and above the generalized apprehension that every citizen must experience when providing information to the FBI pertinent to criminal activity. For example, an inside informant would reasonably have a greater expectation of confidentiality than someone who is merely providing business records after the fact that might enable the FBI to link a suspect to a crime. Examples of sources who might have a heightened reason to expect that their identities and information will be kept confidential by the FBI unless used at trial include the following: (1) a person in close relationship to the defendant (e.g., a member of the defendant’s family or associate of the defendant), with a reason to fear retaliation or harassment,
Ferguson v. F.B.I.,
Institutional sources may also assert implied agreements of confidentiality, but
Landano
cautions us again to require specificity to uphold a claim of confidentiality for institutions.
See Landano,
III.
In reviewing the actual documents withheld in this case, we are once again hampered by the failure of the district court to conduct a “source-by-source” analysis of the documents as to which the government is asserting implied confidentiality, Hale II, at 1057. Instead, the district court focused on the nature of the crime, and apparently assumed that was sufficient to imply confidentiality as to all the documents withheld. As noted earlier in this opinion, we reject that conclusion. What few references that the district court did make regarding the source’s relationship to the crime were so generic that they provide us with no basis for reviewing whether an implied understanding of confidentiality is reasonable to assume as to any particular source. E.g., district court order at 6. (“[Witnesses or sources of information could reasonably expect to have fear of retaliation and would logically have a fear of death or bodily harm as a consequence of their cooperation with a law enforcement agency.”). The district court also referred to a subcategory of documents reflecting communications involving “commercial or financial institutions.” Id. at 4. However, once again the court did not provide any particularized findings to support the government’s claim of confidentiality. The court merely stated that these documents were properly withheld since “[b]y its nature, the release of *1033 the information would necessitate the identification of the source.” Id. at 4-5. 7 The question, however, is not whether release of the information will reveal the source, but rather whether there was an implied agreement of confidentiality given when the source provided the information to the government investigators.
Our in camera review of the documents in dispute and our review of the United States’ Vaughn affidavit, 8 do not enable us to determine, with any degree of confidence, whether the government appropriately or inappropriately claimed a 7(D) exemption pursuant to implied confidentiality as to the various sources. We have identified several sources where implied confidentiality might be justified based on a source’s relationship with Hale. However, in at least one situation the confidential source has already been identified by the government to Hale, and it is not at all evident why certain portions of the information from that source has been deleted and other portions produced. We are also unpersuaded from the Vaughn affidavit that the government has established an adequate justification to withhold information from commercial and financial sources as referenced in paragraph 37 of the Vaughn affidavit. Other sources that have been deleted lack any particularized justification to support a conclusion that the source provided information under an implied agreement of confidentiality.
Therefore, we must once again remand this case for further proceedings. As to each source whose identity has not been disclosed and as to each category of material deleted from a source whose identity has been disclosed, the district court is requested to make explicit findings, consistent with this opinion, explaining why such deletions are or are not justified under Exemption 7(D). Any such justification will have to be grounded upon the source’s relation to Hale or the crime rather than solely upon the nature of the crime alone. And, a mere relationship with Hale or the crime will not automatically support a 7(D) exemption unless a finding is made explaining why that source would reasonably expect that the information provided would be kept confidential notwithstanding the failure of the source to request or receive an express promise of confidentiality.
We recognize that this further inquiry may require a further in camera submission by the government, and it may require a portion or all of the district court’s order to be filed under seal and not disclosed to the parties or the public. However, unless the government is truly put to its proof under the Landano standard and unless the district court is required to address the claimed implied confidentiality on a source-by-source basis, we have no realistic way of reviewing the claimed 7(D) exemptions and Hale is left without a real mechanism to have the government’s claim of exemption challenged.
IV.
Based upon the foregoing discussion, we AFFIRM the district court’s ruling upholding the government’s claims of exemption on the basis of express confidentiality agreements; we REVERSE the district court’s rulings as to implied agreements of confidentiality; and we REMAND this matter to the district court for further proceedings consistent with this opinion.
Notes
. Exemption 7(D) permits the government to withhold "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] information furnished by a confidential source” in the course of a criminal investigation. 5 U.S.C. § 522(b)(7)(D).
. Prior to
Landano,
we interpreted Exemption 7(D) as permitting a presumption that promises of confidentiality are implicit in FBI interviews conducted as part of a criminal investigation.
Johnson v. United States Dep’t of Justice,
. The United States continues to withhold certain requested materials on the grounds that other exemptions to the FOIA apply. The district court's prior determination that these materials were properly withheld on other FOIA grounds was affirmed on appeal by this court in Hale I, and those claims of exemption are no longer at issue. The only FOIA exemption at issue here is Exemption 7(D).
. The United States argues that our
de novo
review need not include an
in camera
review of the documents in dispute. The United States contends that (1) § 552(a)(4)(B) of the FOIA, which provides for
in camera
review of documents requested pursuant to the FOIA, contemplates an
in camera
review by the district court, 5 U.S.C. § 552(a)(4)(B) ("On complaint, the district court ... has jurisdiction to enjoin the agency from withholding agency records and ... may examine the contents of such agency records in camera ....”), and (2)
in camera
review is the exception and not the rule,
see National Labor Relations Board v. Robbins Tire & Rubber Co.,
We conclude that, although an
in camera
review is not always required, nothing precludes us on appeal from exercising our discretion to review the disputed documents
in camera.
In this case, the district court’s conclusions were based on an
in camera
review of the documents and the court's ultimate findings, as reflected in its order, were inadequate and provide an insufficient basis upon which to predicate our review. Under these circumstances
in camera
review at the appellate level is appropriate.
See Oliva v. United States Dep’t of Justice,
. In conducting the source-by-source review, we must look to the circumstances at the time the communication was made to the FBI.
See Landano,
. The government "need not provide so much detail that the confidentiality is destroyed.”
Church of Scientology,
. The district court set forth the following relevant findings of fact:
|T]he victim of the kidnaping for which [Hale] was convicted was a bank officer and his parents were bank officers and the major stockholders of the bank. Bank funds were also utilized to pay ransom money. Employees of financial institutions provided information from bank records, and the source of the information knew that the material provided was confidential and available to only a few persons.
District court order at 4 — 5.
. We discuss here only that information withheld solely on the basis of Exemption 7(D). We do not consider any information which was also withheld pursuant to another exemption because these other exemptions have already been evaluated and affirmed by this court. See supra n. 3.
