Technical Report 08-05 March 2008 - Changes in Espionage by Americans: 1947-2007, by Katherine L. Herbig, Northrop Grumman Technical Services. Released By – James A. Riedel [via FAS]

"Since 1987, the Defense Personnel Security Research Center (PERSEREC) has maintained a database on espionage by American citizens based largely on open sources, and has collected files on each of the 173 individuals in the database. Espionage by Americans is the worst outcome for the personnel security system that works to reduce the risk of insider threat. Although its main focus is the personnel security system, PERSEREC monitors and analyzes espionage by Americans in order to improve understanding of this betrayal of trust by a small minority of citizens. This report is the third in a series of technical reports on espionage based on the PERSEREC Espionage Database, files of information from the press, and scholarship on espionage. The focus of this report is on changes and trends in espionage by Americans since 1990, compared with two earlier periods during the Cold War."