U.S. flag

An official website of the United States government, Department of Justice.

NCJRS Virtual Library

The Virtual Library houses over 235,000 criminal justice resources, including all known OJP works.
Click here to search the NCJRS Virtual Library

Patterns of Lone Actor Terrorism in the United States: Research Brief

NCJ Number
Brent L. Smith; Paxton Roberts; Jeff Gruenewald; Brent R. Klein
Date Published
3 pages

This research examined the differences in geospatial and temporal patterns between lone actor and group-based terrorists in the United States.


Differences examined pertained to demographics, precursor activities proximity to the terrorism incidents, and longevity of conducting terrorist activities. Data for the analysis came from the American Terrorism Study (ATS), which includes information on federal criminal cases resulting from FBI investigations for “terrorism or terrorism-related activities.” Data were analyzed from 264 prevented or completed terrorism incidents in the United State during the period from 1980 to the current date (2015). The cases examined involved 314 indictees charged with just over 3,000 federal criminal counts. They were responsible for 1,788 recorded precursor activities that occurred at just over 1,100 geocoded addresses. The study found that lone-actor terrorists are relatively rare, composing less than 10 percent of all terrorists known in the United States during the study period; however, lone actors were responsible for a disproportionate number of terrorist incidents in the United States, i.e., 65 of 264 (25 percent). Terrorists are overwhelmingly male and have completed a high school curriculum or some college courses. They are likely to be married and in their mid-thirties in age. Compared to group participants, lone actors are more likely to be male and better educated than their group-participant counterparts. Lone actors are also significantly less likely to be married than group participants. On average, lone-actor terrorists have a significantly longer life span as terrorists than group participants.