Latest GRIEVANCE Publications

Lone Actor Terrorists: A Residence-to-Crime Approach

Zoe Marchment, Noémie Bouhana and Paul Gill


As an individual navigates their city or town, travelling to and from their daily activity nodes (such as place of work or education, places of socializing or recreation) they will become more familiar with some areas than others. This increased familiarity increases the likelihood that these individuals will offend within that space, as they are more aware of criminal opportunities, as well as associated risks (such as chances of detection and interdiction). An offender’s journey-to-crime will typically demonstrate the distance decay effect, whereby the chances of offending and frequency of offences will decrease as the distance from the individual’s home increases. Where an individual has several equally attractive alternatives, they generally prefer the one that is closest to them.


Using a unique dataset of 122 attacks committed by 70 lone actor terrorists, we investigated the spatial decision making of lone actor terrorists in Europe and the United States. Journey-to-attack distances were computed for each attack using the home and target locations using Euclidean straight-line distance (the shortest distance between two points). Target choices were coded as either iconic, symbolic, or arbitrary.


The distance decay function that is evident for traditional crimes was replicated for lone actors - with the results demonstrating that frequency of attacks decreases as distance from home locations increases. Collectively, the statistical analyses and illustrative examples suggested that distance can be put forward as a constraining factor that governs the selection of targets. We conclude that lone actor target selection is a result of a confluence of distance and appropriate targets, whereby a target will be chosen where it is a) in the individual’s awareness space, b) within close proximity to the individual’s home location, and c) relevant to the individual’s ideology.

·      Lone actors tend to travel short distances to commit their attacks. 70% of attacks in Europe occurred within 5 miles of the offender’s home.

·      Individuals with links to a wider network travelled much further than those without. Those who had face-to-face interactions were over four times more likely to travel further than 10 miles.

·      The constraining effects of distance are different for the U.S. and Europe. The results for both continents demonstrate the distance decay pattern, but to a different degree, with individuals in the U.S. travelling further than those in Europe.

·      Individuals travelled further for iconic targets than symbolic or arbitrary targets, and further for symbolic targets than arbitrary targets. They also travelled much further for attacks where a symbolic building was present when compared with symbolic people. This suggests that a consideration of costs vs. benefits may take place in decision making regarding target selection, and that there is a trade-off between distance to the target and the representative value of the target.

·      Islamist and right-wing lone actors may behave in a similar way to “traditional” criminals in terms of spatial decision making when selecting targets. However, single-issue actors do not seem to be constrained by distance in the same way, possibly as many of this subgroup have a limited choice set of targets to choose from. For example, anti-abortionists in the U.S. may be forced to travel to different states due to the varying legality of abortions in different states.

Case Study:

Benjamin Nathaniel Smith was a right-wing extremist who killed 2 individuals and injured 10 in targeted attacks on ethnic minorities over a 3-day period in 1999. Smith began his attacks in the neighbourhoods surrounding his childhood home in Wilmette, where he had recently returned to live. These neighbourhoods were predominantly populated by Orthodox Jews as well as large numbers of immigrants. The following day, attacks took place at the first university he attended as well as two of the closest towns to the university by direct route. Finally, on the Sunday, he waited outside a Korean Methodist church near the second university he attended, before killing a graduate student as the congregation emerged. Smith had just finished his third year of college at this university, and was living in student accommodation less than half a mile away from this campus until a few months before his attacks.

This case highlights the importance of considering all locations in the individual’s awareness space, including previous addresses, places of work and education, as well as the areas surrounding their home.

Full citation:

Marchment, Z., Bouhana, N., & Gill, P. (2018). Lone Actor Terrorists: A Residence-to-Crime Approach. Terrorism and Political Violence, 1-26.