Lone Actors as a Challenge for P/CVE

The increase in lone-actor terrorist attacks in Europe is concerning: lone actors’ relative isolation compared to group actors, as well as the near-spontaneous character of their attacks, have made it harder for law enforcement to detect and disrupt their plans. The latest Europol terrorist threat assessment highlights that in 2020 all completed jihadist attacks in the EU were committed by individuals acting alone, while most foiled plots by jihadists involved multiple suspects.

Much of our understanding of lone actors has been sourced from data sets spanning the period 1940–2015, so as to ensure large enough samples for analysis. Recent efforts focus on creating smaller and richer data sets from 2015 for more contemporary relevance. This paper provides an overview of past research and discusses more recent lone-actor profiling and their psychology, as well as the challenge of identifying lone actors.