David Canter suggested that people reveal themselves through the locations where they commit crimes. Geographic profiling is the process of determining the most probable area of an offender’s base of activities through an analysis of his or her crime locations (Rossmo, 2000).
Geographical profiles are used in the investigation of a series of crimes to locate the likely home base of the offender. This base could be where the offender lives, but could also be a place of employment, friend or families house, or significant previous home. It could be any place that is meaningful to the offender.
Canter (2003) argues that geographical profiling was “born” in 1980 when a UK police investigator analysed the locations of crime scenes of the Yorkshire Ripper and computed the “centre of gravity” of the crime scenes thought to be linked to the case. It turned out that the offender lived in the town that the investigator predicted.
In the mid-1990s, more sophisticated models for predicting an offender’s home address were developed. These were building on the research conducted by Brantingham and Brantingham (1981). Rossmo (1999) summarized the research in this area which has been that most crimes occur in relative proximity to the offender’s home. Why travel 10 miles when what you want is available in 1?
Crime trips follow a distance-decay function, with the number of crime occurrences decreasing with distance from the offender’s home. In other words, the further away, the less crime. There has found to be differences in the distance travelled to offend for various crime types.
Research has shown that the most important influence on where criminals offend is where they go during their non-criminal activities (Bennett & Wright, 1984). These distances can be written into a mathematical model which is then used to predict the most likely home base of the offender. In doing this, investigative resources can be applied in a more targeted way. This mathematical equation has been used in several software programs to predict where the offender will live or work.
In some serial crime cases, the number of known suspects can be in the hundreds or thousands, and a geographic profile can help police manage this information (Rossmo, 2012). A geographic profile is used to prioritize suspects based on their address information. Analysts can use a geographic profile to prioritize records the police department already has access to, such as arrest records, field interviews, and jail booking sheets. These files often include the offender’s address, physical description, and prior arrest charges. Other databases may also be used in conjunction with a profile, such as parole, probation, and motor vehicle registration databases (Rossmo, 2006).
While it does not directly solve cases, geographic profiling can spatially focus an investigation and help manage large volumes of information.