For future requesters who might be interested in the records generated by Special Counsel Robert Mueller, who was appointed by DOJ yesterday to oversee an investigation into Russian contacts with the Trump campaign, the following FOIA case involving former Special Counsel Patrick Fitzgerald's investigation into the Valerie Plame affair might be instructive:  Citizens for Ethics & Responsibility in Wash. v. DOJ, 658 F. Supp.2d 217 (D.D.C. 2009).    

In sum, the court held that DOJ properly withheld certain records pursuant to Exemptions 1, 3, 5 (deliberative process privilege), 6, and 7(C), but that it failed to demonstrate the applicability of Exemption 7(A) to "specific ongoing or reasonably anticipated law enforcement proceedings."  Requesters seeking Mueller's investigatory records will likely have to wait years, like CREW, until the government's investigation and any anticipated law enforcement proceedings moot Exemption 7(A).