Updating and organising our knowledge of risk and protective factors for lone-actor terrorism.

This chapter updates builds upon previous descriptive analyses of lone-actor terrorists, their behaviours, ideological backgrounds and degrees of loneness. It offers greater conceptual clarity, updated data and a more expansive set of variables from previous analyses. Individual vulnerability indicators examined here include potential indicators of cognitive susceptibility to moral change, and self-selection and social selection into radicalizing settings, notably membership of a social network containing one or more radicalized individual. We also examine exposure settings, attack-preparation behaviours and explore sub-set analyses of the data. The analyses informed by a Risk Analysis Framework which offers a multilevel, integrated meta-model of these events and allows for the synthesis of disparate findings. The analyses provide key insights into the behaviour of lone-actors, which could inform intelligence gathering and investigative practice, as such analyses already do in other crime prevention domains.