Exemption 8(1)(g)
RTI: Exemption 8(1)(g)
(g) information, the disclosure of which would endanger the life or physical safety of any person or identify the source of information or assistance given in confidence for law enforcement or security purposes;
FOIA Exemption 5 U.S.C. ยง552(b)(7)(D) reads:
(D) could reasonably be expected to disclose the identity of a confidential source, including a State, local, or foreign agency or authority or any private institution which furnished information on a confidential basis, and, in the case of a record or information compiled by criminal law enforcement authority in the course of a criminal investigation or by an agency conducting a lawful national security intelligence investigation, information furnished by a confidential source,
There has been extensive litigation in this field. Most cases have involved FBI records requested by subjects of FBI investigations. Under the FOIA and Privacy Act, FBI is required to give its files about an individual to that individual, (once the investigation is over, or if a case is not filed for prosecution). However such files may contain information supplied by FBI informants, as well as identity of informants. Many times identity of the informant can be deduced by looking at the information supplied by the informant. Courts have refused to give FBI a blanket exemption for all informants. Confidentiality is determined on a case-by-case basis. Only if the informant had a reasonable expectation that his identity would not be revealed to the subject of investigation, then the records may be withheld.
See Landano v Dept. of Justice (US Supreme Court 1993)