## Facts

- Advocacy and legal organizations submitted FOIA requests to multiple federal agencies seeking electronically stored records about the origins, implementation, and expansion of the Secure Communities program, which connected local fingerprinting to federal immigration databases.
- The requests sought, among other categories, policies, guidance, interagency communications, jurisdiction-specific implementation records, and materials linked to FBI biometric initiatives.
- The agencies conducted keyword-based searches of electronic systems, using a limited set of agreed-upon keywords, and produced large volumes of records.
- Plaintiffs asserted that additional responsive records existed and challenged both the adequacy of the searches and the adequacy of the agencies’ supporting declarations.
- The agencies withheld certain information under FOIA exemptions, including law-enforcement-related exemptions, sometimes relying on a “mosaic” rationale (that small pieces of information could become harmful when combined).
- The case came before the district court on cross-motions for summary judgment concerning search adequacy, affidavit sufficiency, and exemption withholdings.

## Issues

1. Whether the agencies’ keyword-based searches for electronically stored information were reasonably calculated to uncover all relevant documents under FOIA.
2. Whether the agencies’ declarations were sufficiently detailed and nonconclusory to permit judicial review of search methods and withholdings.
3. Whether the agencies adequately justified FOIA exemption withholdings, including withholdings premised on a “mosaic” theory of harm.

## Decision

- The court granted in part and denied in part the agencies’ summary-judgment motions and granted in part and denied in part plaintiffs’ cross-motion.
- The court upheld adequacy determinations for searches supported by detailed, supervised, well-documented protocols and declarations.
- The court denied summary judgment where agencies failed to describe, supervise, or document how custodians applied keywords, what systems were searched, and why repositories were included or excluded.
- The court upheld some exemption withholdings supported by specific explanations linking particular information to a foreseeable harm.
- The court rejected conclusory, categorical invocations of the mosaic theory and ordered additional explanation and, where appropriate, further disclosure or reevaluation.
- The court directed certain agencies to conduct additional or revised searches and/or submit supplemental declarations curing deficiencies.

## Legal Principles

- A FOIA search is adequate if it is reasonably calculated to uncover all relevant documents; FOIA requires reasonableness, not perfection.
- When requests target electronically stored information, the adequacy of a search depends heavily on the search protocol’s design and implementation, including term selection, system coverage, and oversight of custodians performing searches.
- Agency declarations must be reasonably detailed, nonconclusory, and specific enough to allow meaningful judicial review; “trust us” assurances and recitations of statutory standards are insufficient.
- To support summary judgment, an agency must explain the scope of repositories searched, how custodians and systems were selected, what instructions and quality controls were used, and why likely locations were not searched.
- The mosaic theory may support withholding only if the agency provides a reasonably detailed, particularized explanation of how disclosure of the specific information at issue could cause the exempted harm; it is not a standalone justification.

## Conclusion

The court required rigor in FOIA searches for electronically stored information, holding that agencies must document and supervise keyword-based protocols through detailed, nonconclusory declarations, and that exemption withholdings—especially those relying on mosaic reasoning—must be tied to specific, explained harms rather than generalized assertions.


Nat'l Day Laborer Org. Network v. U.S. Immigr. & Customs Enf't Agency, 877 F. Supp. 2d 87 (S.D.N.Y. 2012)