This report provides an overview of violent incidents and plots committed or attempted by supporters of al-Qa’ida and affiliated movements (AQAM) who targeted the United States between 1990 and 2013. Since the September 11, 2001 (9/11) terrorist attacks, countering the dynamic threat of future AQAM attacks has understandably been a top priority under the broader homeland security mission. A key to terrorism prevention is developing a comprehensive understanding of the patterned nature of the AQAM threat in the United States. Such an understanding begins with clear definitions and rich descriptions of AQAM-related offenders and incidents. There have been several efforts to chronicle successful, failed, and foiled AQAM-related plots against the United States. We believe, however, that the systematic definitional, data collection, and analytical approaches and procedures we have used allow us to fill key gaps in what is known about violence perpetrated by supporters of AQAM.
The data on AQAM-related violence analyzed in this report come from the United States Extremist Crime Database (ECDB). These data are unique as they include information on violent crimes in which AQAM supporters were indicted at either the state or federal level. These data also cover successful fatal attacks and unsuccessful plots involving both lone actors and group-based offenders who support AQAM. Finally, and importantly, violent crime data from the ECDB allow for the disaggregation of two types of planned but ultimately unsuccessful violent incidents based on whether general or specific targets were identified. Each event that involves a spatially unique target, whether general or specific in nature, is considered a separate incident or plot.
 If prosecutors dropped charges against the perpetrators or perpetrators were acquitted on all related charges, they are not included in this report. Perpetrators who were killed carrying out violent attacks are included.
Gruenewald, Jeff, and Joshua D. Freilich, Steven M. Chermak, William S. Parkin. “Violence Perpetrated by Supporters of al-Qa’ida and Affiliated Movements (AQAM): Fatal Attacks and Violent Plots in the United States,” Report to the Resilient Systems Division, Science and Technology Directorate, U.S. Department of Homeland Security. College Park, MD: START, 2014. http://www.start.umd.edu/pubs/START_ECDB_ViolencePerpetratedbySupportersofAQAM_June2014.pdf