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.
Development.
While the use of spatial analysis methods in police investigations goes back many years (think of 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 model is based on the assumption that offenders are more likely to select their victims and commit a crime which would be centered near their home address. The technique has now spread to several U.S., Canadian, British, and European law enforcement agencies. Originally designed for violent crime investigations, it is increasingly being used on property crime.
Through numerous research studies, there has been an increased importance placed on the journeys offenders habitually take to determine the spatial range of criminal activity. These areas become a comfort zone for predatory offenders to commit their crime because of their familiarity. Consequently, criminal acts follow a distance-decay function, such that the further away the regular activity space of an offender is, the less likely that the person will engage in a predatory criminal activity. However, there is also a buffer zone where an offender will avoid committing crimes too close to their homes in the likely event that they will be identified by a neighbour.
Central concepts.
The theoretical foundation of geographic profiling is in environmental criminology. Key concepts include:
Furthermore, serial crimes are the easiest to develop geographic profiles, since each crime contains new spatial information and provides additional data including the fact that crime area tends to enlarge with an increase of comfort and confidence. The initial hunt and criminal acts are most likely to occur relatively close to the location of the offender's home or workplace. As the success rate increases, there will be a burgeoning sense of confidence to seek his prey further from home and to travel a greater distance. Crimes that are suitable for analysis are those that are predatory in nature and exercises 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 detailed around the circle theory of environmental range. In 1993, Canter and Larkin developed two models of offender behaviour: marauder and commuter models. The distinction is that marauders operate in an area that is in close proximity of the offender's home base while commuters commit crimes far outside of the habitual zone. It hopes to differentiate the two types of serial offenders by studying the relationship of the criminal spatial behaviour to the offender's place of residence.
Considerations.
In developing a geographic profile, there are important factors to consider:
A crime will contain evidence. The evidence found at the location provides information leading to the offender and victim's prior location, 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.
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 into him using different seemingly harmless situations. 
Hunting process can be broken down into two parts. (1) The search for a suitable victim, and (2) the method of attack. 
“Target or victim backcloth is important for an understanding of the geometric arrangement of crime sites; it is the equivalent of the spatial opportunity structure (Brantingham & Brantigham, 1993b). It is configured by both geographic and temporal distribution of “suitable” (as seen from the offenders perspective) crime targets or victims across the physical landscape. The availability of particular targets may vary significantly according to neighborhood, area, or even city, and is influenced by time, day of week, and season; hence, the term structural backcloth is also used.”
Large Roads and highways play a huge part in crime strictly because it how both criminals and victims are forced to travel. Crimes will often cluster around freeway exits and entrances.
These are two forms of rapid transportation that may also be used by offenders and victims and can be hot spots in certain areas. 
Offender and victim alike are both restrained by physical boundaries such as rivers, lakes, oceans or highways. Psychological boundaries may also affect movement, for example a black offender may not travel into a white neighborhood for fear or being identified. 
Certain offenders prefer a certain ethnicity of victim, if so then he may hunt in different neighborhoods affecting spatial crime patterns. 
Understanding the routine of a victim may provide insight into how the offender searches for his victims. 
Incorporating these factors in a profile can lead to a geographic pattern where it sheds light on an offender's mobility, method of transportation, ability to navigate boundaries and most importantly, the possible residential location. It is important to recognize such spatial intentionality, to determine the offender's comfort zone and their desire to commit crimes in locations where they feel a sense of familiarity. However, the reality may be more complex since an offender may have multiple spatial anchor points, such as home, workplace or the residence of their significant other.
Tools.
Geographic profiling is an investigative tool that can be seen as a strategic information management system to assist police with the large volume of information throughout an investigation. It concentrates its focus on the geographic aspects of the crime and was developed in response to the demands of solving serial crimes. In response, Rossmo developed a computerized geographic profiling algorithm called criminal geographic targeting (CGT) which assess the spatial characteristics of crimes. It analyzes the geographic coordinates of the offender's crimes and produces a color map which assigns probabilities to different points for the most likely area of the offender's home base. CGT has been patented and integrated into a specialized crime analysis software product called Rigel. The Rigel product is developed by the software company Environmental Criminology Research Inc. (ECRI), which Rossmo co-founded.
Geographic Profilers often employ tools such as Rigel, CrimeStat or Gemini to perform geographic analysis. System inputs are crime location addresses or coordinates, often entered through a geographic information system (GIS). Output is a jeopardy surface (three-dimensional probability surface) or color geoprofile, which depicts the most likely areas of offender residence or search base. These programs assist crime analysts and investigators to focus their resources more effectively by highlighting the crucial geographic areas.
Geographic Profiling Analysis (GPA) training.
Geographic profiling is a sub-type of offender or criminal profiling (the inference of offender characteristics from offence characteristics). It is therefore related to psychological or behavioral profiling. If psychological profiling is the "who," geographic profiling is the "where." All certified geographic profilers are members of the International Criminal Investigative Analysis Fellowship (ICIAF), a professional profiling organization first begun by investigators trained by the FBI in the mid-1980s.
A Geographic Profiling Analysis (GPA) training programme has also been created and is governed by the Committee for GPA Training and Certification (CGPATC). The program has been designed so that geographic profiling analysis remains a recognized law enforcement tool; a meaningful certification for crime analysts and detectives; a standard of quality through adequate qualifications in law enforcements is maintained; and finally to establish an ethical code of conduct.
Limitations.
Although geographic profiling is a useful tool for assisting investigations, e.g. in prioritizing suspects, like any other models there are certain limitations:
See also.
General:
References.
Washington, DC: American Psychological Association