Behavior Associations in Lone-Actor Terrorists

Terrorist attacks carried out by individuals have significantly accelerated over the last 20 years. This type of lone-actor (LA) terrorism stands as one of the greatest security threats of our time. While the research on LA behavior and characteristics have produced valuable information on demographics, and warning signs, the relationship among these characters is yet to be addressed. Moreover, the means of radicalization and attacking have changed over decades. This study conducts an a-posteriori analysis of the temporal changes in LA terrorism and behavioral associations in LAs. We first identify 25 binary behavioral characteristics of LAs and analyze 190 LAs. Next, we classify LAs according to behavioral clusters obtained from the data. Within each class, statistically significant associations and temporal relations are extracted using the A-priori algorithm. The results indicate that while pre-9/11 LAs were mostly radicalized by the people in their environment, post-9/11 LAs are more diverse. Furthermore, association chains for different LA types present unique characteristic pathways to violence and after-attack behavior.