ABSTRACT
Research on lone-actor terrorism grew exponentially in the past decade. Whilst certainly not a fundamentally new phenomenon (for historical accounts, see Coffey, 2011; Bach Jensen, 2014; Kaplan, 1997; Michael, 2014; van Buuren & de Graaf, 2014), it has been occurring with greater frequency over the past two decades (Appleton, 2014; Coffey, 2011; Eby, 2012; Nesser, 2012). Some studies provide more conservative figures than others (COT, 2007), but by and large the consensus appears to be that ‘lone wolf terrorism is on the rise by all accounts, and by every indicator’ (Feldman, 2013, p. 270). There is also data to suggest that lone-actor extremist attacks have increased in lethality over the past two decades (Teich, 2013) or may be even more lethal than group-based attacks in certain contexts (Phillips, 2015). Even so, lone-actor extremist events remain a marginal phenomenon compared to group-based terrorism, and the latter is, on balance, still considerably more deadly (Nesser, 2014; Spaaij, 2010).>
