32 C.F.R. § 147.24

The National Agency Check is a part of all investigations and reinvestigations. It consists of a review of;

(a) Investigative and criminal history files of the FBI, including a technical fingerprint search;

(b) OPM's Security/Suitability Investigations Index;

(c) DoD's Defense Clearance and Investigations Index;

(d) Such other national agencies (e.g., CIA, INS) as appropriate to the individual's background.