This research note argues that the “lone wolf” typology should be fundamentally reconsidered. Based on a three-year empirical research project, two key points are made to support this argument. First, the authors found that ties to online and offline radical milieus are critical to lone actors' adoption and maintenance of both the motive and capability to commit acts of terrorism. Second, in terms of pre-attack behaviors, the majority of lone actors are not the stealthy and highly capable terrorists the “lone wolf” moniker alludes to. These findings not only urge a reconsideration of the utility of the lone-wolf concept, they are also particularly relevant for counterterrorism professionals, whose conceptions of this threat may have closed off avenues for detection and interdiction that do, in fact, exist.

The background for this paper is the debate over what role mental illness plays in radicalization to violent extremism. While one camp points to cases of abnormal functioning of perpetrators, another argues that normal psychological mechanisms are central. Through a review of these perspectives, it becomes clear that mental illness cannot be ruled out as an epi‐phenomenon, but is not a necessary condition either. The paper draws on work in psychiatric nosology on dimensional and categorical conceptions of illness and argues that the perspectives in this literature reflect a categorical approach to normal and abnormal functioning. Under a dimensional perspective, findings converge. The paper concludes by showing how this new dimensional approach to the role of mental illness in radicalization has implications for the design of risk assessment tools and leads to the recommendation for stronger inter‐agency cooperation between mental health professionals, social services, and police and intelligence services.

This article provides a comparative analysis of lone-actor terrorist radicalization from a relational perspective. Extant research on lone-actor terrorism has shown that lone actors are rarely as “lone” as public perceptions suggest. In most cases, lone-actor terrorists have some social ties to established radical groups. Accordingly, this article asks (1) why these individuals do not integrate into the radical groups they frequent and engage in collective violence, and (2) if they do integrate, why do they then end up engaging in violence on their own? The article argues that patterns of lone-actor terrorist radicalization can be categorized according to the extent and evolution of their loneness. It highlights two broad patterns of lone-actor radicalization in relation to broader radical groups/movements – peripheral and embedded – and explores the reasons why some lone-actor terrorists remain peripherally integrated in radical groups, while others become more embedded only to engage in violence alone. The article is based on qualitative research, drawing on a geographically and ideologically diverse sample of cases (N = 25), and access to restricted material. The article identifies and theorizes five recurrent radicalization trajectories, which are variations of the peripheral and embedded patterns, and discuss the implications for prevention/interdiction.

Effective risk communication is an integral part of responding to terrorism, but until recently, there has been very little pre‐event communication in a European context to provide advice to the public on how to protect themselves during an attack. Following terrorist attacks involving mass shootings in Paris, France, in November 2015, the U.K. National Police Chiefs’ Council released a Stay Safe film and leaflet that advises the public to “run,” “hide,” and “tell” in the event of a firearms or weapons attack. However, other countries, including Denmark, do not provide preparedness information of this kind, in large part because of concern about scaring the public. In this survey experiment, 3,003 U.K. and Danish participants were randomly assigned to one of three conditions: no information, a leaflet intervention, and a film intervention to examine the impact of “Run, Hide, Tell” advice on perceptions about terrorism, the security services, and intended responses to a hypothetical terrorist firearms attack. Results demonstrate important benefits of pre‐event communication in relation to enhancing trust, encouraging protective health behaviors, and discouraging potentially dangerous actions. However, these findings also suggest that future communications should address perceived response costs and target specific problem behaviors. Cross‐national similarities in response suggest this advice is suitable for adaptation in other countries.

This article explores the link between radicalization patterns and modes of attack planning and preparation among lone-actor terrorists. Building on theorized patterns of lone-actor radicalization, we discuss and compare their modes of pre-attack behavior, including target and weapon choice, observance of operational security measures, likeliness of engaging in leakage behavior, and the overall amount of time devoted to these activities. This exploratory study builds upon a dataset of thirty-three lone-actor terrorist cases in North-America and Europe between 1986 and 2015. The analysis suggests that specific patterns of radicalization are linked to systematic differences in modes of attack planning and preparation. The results provide insights into the heterogeneity of terrorist involvement and tentatively suggest the potential importance for law-enforcement agencies in using case-specific knowledge on radicalization patterns to inform forecasts of likely pre-attack behaviors.

This article explores the phenomenon of Islamist foreign fighters, more specifically the movement of European Muslims to participate in the insurgencies in Syria and Iraq connected to the Islamic State/Daesh as well as the anti-Assad forces in Syria and the implications for European state stability. Drawing on personal psychology, social psychology, and social movement theory the article offers an integrated theoretical framework to analyze the radicalization of Islamist foreign fighters. Building on Danish data of Islamist foreign fighters, the article provides a first test of the analytical usefulness of this framework. The article further considers what distinguishes the Islamists that go from those that under similar circumstances stay behind, and whether this is a differences of kind or a difference of degree. Finally, we discuss the question of how much of a threat foreign fighter returnees pose to European states.