How do offenders choose where to offend? Perspectives from animal foraging

Purpose Research suggests that offender spatial decision-making is not random. However, little is known about if or how offences in a series influence where an offender will target next. Drawing on concepts and empirical findings from environmental criminology and the ecology literature, in this article I consider what spatial patterns might be expected in the sequential crimes committed by serial offenders and provide an empirical example. Methods Data for detected burglars are analysed and patterns in the inter-event distances for sequential offences compared with those signatures typically associated with three types of foraging behaviour – central place foraging, Brownian walks and Levy walks. Analyses involve the use of a Monte Carlo simulation to derive an expected distribution for central place foraging, while the observed probability density function of sequential inter-event distances is compared to exponential and power law distributions to test for evidence of Brownian and Levy walks, respectively. Results Analyses suggest that patterns in burglar sequential inter-event distances cannot be explained by a simple central place foraging strategy. The distribution of sequential inter-event distances is found to be consistent with both Brownian and Levy walks. Conclusions The findings suggest that there are regularities in the sequential spatial choices made by offenders, and that these are similar to those observed across species. Reasons for why there is evidence of both Brownian and Levy walks are discussed. The implications of the findings for forensic techniques such as crime linkage analysis, geographic offender profiling and crime forecasting are discussed.