Geographic profiling is a criminal investigative methodology that analyzes the locations of a connected series of crimes to determine the most probable area of offender residence. By incorporating both qualitative and quantitative methods, it assists in understanding spatial behaviour of an offender and focusing the investigation to a smaller area of the community. Typically used in cases of serial murder or rape (but also arson, bombing, robbery, terrorism and other crimes), the technique helps police detectives prioritize information in large-scale major crime investigations that often involve hundreds or thousands of suspects and tips. In addition to determining the offender's most likely area of residence, an understanding of the spatial pattern of a crime series and the characteristics of the crime sites can tell investigators other useful information, such as whether the crime was opportunistic and the degree of offender familiarity with the crime location. This is based on the connection between an offender's behavior and his or her non-criminal life. Geographic profiling is growing in popularity and, combined with offender profiling, can be a helpful tool in the investigation of serial crime.
Development While the use of spatial analysis methods in police investigations goes back many years (e.g. detectives gathered around a large city map with pins stuck in it), the formalized process known today as geographic profiling originated out of research conducted at Simon Fraser University's School of Criminology in British Columbia, Canada, in 1989. Geographic profiling is based on the assumption that offenders tend to select victims and commit crimes near their homes. The technique has now spread to several US, Canadian, British, and other European law enforcement agencies. Originally designed for violent crime investigations, it is increasingly being used on property crime. Through numerous research studies, more importance has been placed on the journeys offenders habitually make to determine the spatial range of criminal activity. Because of their familiarity, these areas become a comfort zone within which offenders prefer to commit crimes. Consequently, criminal acts follow a distance-decay function, whereby people are more likely to commit offences near their homes. An exception to this is a buffer zone around offenders' homes, within which they avoid committing crimes in case they are identified by a neighbour.
Central concepts The theoretical foundation of geographic profiling is in environmental criminology. Key concepts include:
Journey-to-crime Supports the notion that crimes are likely to occur closer to an offender’s home and follow a distance-decay function (DDF) with crimes less likely to occur the further away an offender is from their home base. It is concerned with the ‘distance of crime’ and that offenders will in general travel limited distances to commit their crimes. Routine activity theory Originally developed by Cohen and Felson (1979), the primary principle is that the offender and victim must intersect in time and space for a crime to occur. This approach focuses on the concept that crime occurs when an opportunity is taken within both parties’ non-criminal spatial activity. An activity space may consist of the regular areas an offender travels such as work, school, home or recreational areas. Rational choice theory Concepts relating to the explanation of spatial behaviour include the least-effort principle where offenders are more likely to act on the first or opportunity and the idea of a buffer zone. It exhibits a constant tension between the offender’s desire to divert attention from his home base and the desire to travel no further than necessary to commit crimes. Crime pattern theory Developed by Canadian environmental criminologists Paul and Patricia Brantingham, the theory exerts the strongest influence in geographic profiling. It suggests that crime sites and opportunities are not random. There is an emphasis in the interaction between the offender’s mental map of spatial surroundings and the allotment of victims (target backcloth). Serial crimes are the easiest to develop geographic profiles for, since each crime contains new spatial information and provides additional data including the fact that the crime area tends to enlarge with an increase of comfort and confidence. The initial hunt and criminal acts are likely to occur close to the offender's home or workplace. As the success rate increases, the criminal's growing confidence will lead him/her to seek his prey further from home. Crimes that are suitable for analysis are those that are predatory and involve some spatial decision-making process such as the area for hunting targets, travel routes, mode of transportation and even body dump sites. Another leading researcher in this area is David Canter whose approach to geographic profiling is based on the circle theory of environmental range. In 1993, Canter and Larkin developed two models of offender behaviour: the marauder and commuter models. The distinction is that marauders operate close to the offender's home while commuters commit crimes far outside the habitual zone. It hopes to differentiate the two types of serial offenders by studying the relationship of the criminal spatial behaviour with the offender's place of residence.
Considerations In developing a geographic profile, there are important factors to consider:
Crime locations A crime will contain evidence. The evidence found at the location provides information leading to the offender and victim's prior locations, clues as to where they may have gone, as well as information depicting what happened. Collecting and comparing clues from numerous crime locations influences the development of the offender's patterns.
Offender type According to Dr. Kim Rossmo there are four different types of offenders with regard to geographic profiling. Hunter: the hunter singles out a specific victim without leaving his home territory. He will commit crimes where he lives. Poacher: a poacher will travel out of his home territory to do his hunting. Troller: A troller will realize an opportunistic encounter while occupied in other activities and then strike. Trapper: a trapper will draw the victim to him using different seemingly harmless situations.
Hunting Methods Hunting process can be broken down into two parts. (1) The search for a suitable victim, and (2) the method of attack.
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