Q.    I am researching a crime that occurred in Vietnam in 1970.  The victim was a civilian.  The Army has disclosed records, redacted substantially using exemptions (b)(6) and (b)(7)(C). Since these records are 46 years old, does FOIA caselaw provide a greater burden on the government to justify non-disclosure?  Many records are witness statements, interviews, investigative reports, and medical records.

A.  The passage of time does not heighten the burden of proof that the government must carry with respect to Exemptions 6 and 7(C).  Indeed, DOJ has opined that "[a]s a general rule, the passage of time serves to increase an individual's privacy interests, even in personal information that was once publically [sic] available."  U.S. Dep't of Justice, Guide to the Freedom of Information Act, Exemption 6, p. 36 (last updated Jan. 10, 2014).    

If you are familiar with any of the third parties involved, it might be worthwhile to investigate whether any are deceased, which would likely result in the disclosure of additional information.  An agency may presume that an individual who would be 100 years old at the time of the request is no longer alive.  See Schrecker v. DOJ, 349 F.3d 657, 662-65 (D.C. Cir. 2003) (upholding FBI's 100-year rule).  Keep in mind that that the D.C. Circuit requires agencies to take basic steps to investigate the life status of third parties.  See Johnson v. EOUSA, 310 F.3d 771, 775-76 (D.C. Cir. 2002).