Profiles of Individual Radicalization in the United States-Foreign Fighters (PIRUS-FF) is a database collected by the National Consortium for the Study of Terrorism and Responses to Terrorism (START) that contains over 100 variables on all phases - pre-travel, travel, and return - of the foreign fighter life cycle. The database currently includes information on 242 individuals who have been publicly identified in open sources as having left, attempted to leave, or expressed an interest in leaving the United States for the purpose of supporting the activities or interests of a foreign non-state armed group or foreign regime, and were motivated by religion, ethnicity, or other ideology. Because many foreign fighters have made multiple trips to a conflict zone, the PIRUS-FF data are coded only for their first known trip. Later versions of the database will include information on individuals' multiple travel attempts, when applicable.
Jensen, Michael, Patrick James, and Herbert Tinsley. 2016. "Overview: Profiles of Individual Radicalization in the United States-Foreign Fighters (PIRUS-FF)." College Park, MD: START. https://www.start.umd.edu/sites/default/files/publications/local_attachments/START_PIRUS-FF_InfographicSeries_April2016_0.pdf