Geographic profiling

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.

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.

The theoretical foundation of geographic profiling is in environmental criminology. Key concepts include:

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.