Marauder
Definition
An offender who operates radially from a fixed anchor point, committing crimes within a radius around that point and returning to it between offences; the spatial model assumed by the circle hypothesis.
- Field
- Geographic profiling
- Behaviour
- Operates radially from a fixed anchor point
- Contrast
- Commuter, who travels away from home to offend
- Associated model
- Circle hypothesis
Common questions
How does classifying an offender as a marauder change a geographic profile?+
If the offender pattern fits marauder behaviour, the profiler can apply spatial models such as the circle hypothesis or Rossmo's formula to estimate the anchor point's likely location from the distribution of crime sites, an approach that does not work if the offender is instead commuting from a distant, unrelated base.
Can an offender switch between marauder and commuter behaviour across a crime series?+
Yes, and this is a recognised limitation of the models; an offender may operate as a marauder for opportunistic offences and travel as a commuter for planned ones, which can distort a profile built on the assumption of a single consistent pattern.
Related terms
- Buffer Zone
- The area immediately around an offender's anchor point where offence probability is suppressed because the offender avoids committing crimes near recognisable locations...
- Circle Hypothesis
- David Canter and Paul Larkin's 1993 hypothesis that for marauder offenders, the anchor point falls within the circle defined by the two...
- Commuter
- An offender who travels from their anchor point into a geographically separate crime area to offend; the circle hypothesis does not reliably...
- Criminal Geographic Targeting (CGT)
- Kim Rossmo's algorithm for geographic profiling, incorporating a distance-decay function modified by a buffer-zone suppression factor; implemented commercially in the Rigel software.
- Distance Decay
- The empirical observation that the probability of an offence location decreases as distance from the offender's anchor point increases, reflecting the rising...
- Geographic Profiling
- A spatial analysis technique originally developed by Kim Rossmo that predicts the likely home or anchor point of a serial offender from...
- Jeopardy Surface
- The probability map output of geographic profiling, rendered as a colour-coded topographic display where high-probability zones for the anchor point appear in...
- Rigel
- The commercial software implementing the CGT geographic profiling algorithm, developed by Environmental Criminology Research Inc. in Vancouver and licensed to law-enforcement agencies...