Serial offenders' spatial behaviour: revisiting the marauder/commuter dichotomy

Geographic profiling is a methodology that uses the location of a series of crimes attributed to the same offender in order to determine the residence of this latter. This recent discipline links the theories of environmental criminology, such as the routine activity theory, with the techniques of spatial analysis offered by the Geographic Information Systems such as centrographic statistics and distance decay functions.

The literature differentiates two categories of serial offenders according to their mobility: the marauder committing his crimes in the nearby area of his home and the commuter travelling outside his daily activities area. Until now, geographic profiling methodologies have proven to be effective only for the marauder behaviours. Before applying these spatial techniques, it is therefore essential to know what kind of offenders we are facing. However, few studies have tried to determine how these two behaviours could be identified on the basis of crime scene information and suspect’s characteristics. Moreover, spatiotemporal aspects have very often been underexploited.

After an introduction to geographic profiling, we present the existing typologies of offender spatial behaviours, among which the commuter/ marauder dichotomy. We set out the crucial information identified in the literature aiming at their differentiation and their implication on the method used to reduce the search area. We draw a conclusion that some spatial inconsistencies persist, requiring to revisit the typologies according to multiple spatiotemporal patterns. Particularly we demonstrate how these typologies can be enhanced by taking into account the relation between the moment of the crime and the location of the crime site. Finally, we show that these new patterns can improve the analysis of commuters thanks to techniques based on spatiotemporal constraints.