Law enforcement agencies are always searching for better ways to identify and apprehend serial offenders, who commit disproportionately more crimes (Canela-Cacho, Blumstein, & Cohen, 1997). Geographic profiling is a suspect prioritization method that can assist with this process.
Geographic profiling is a tool that is especially suited for crime analysts as they are often already familiar with analytical techniques and the creation of crime maps. This article outlines the background of geographic profiling, discusses training in the methodology, and concludes with a case example that shows the application of geographic profiling in an operational case.
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). It is used most often in investigations of serial crimes. This technology assists law enforcement by focusing limited resources, resulting in the apprehension of the offender faster with less time spent and resources expended, and fewer victims. In large investigations, these savings can be significant (Velarde, 2004).
Research has shown that the most important influence on where criminals offend is where they go during their non-criminal activities (Bennett & Wright, 1984). This can be represented through a mathematical model. Geographic profiling focuses the search for suspects using a combination of environmental criminology theory, research on offender spatial behavior, and mathematics, which has been incorporated into geographic profiling software called Rigel by Environmental Criminology Research Inc. (http://ecricanada.com/products/rigel-workstation/). Rigel uses an algorithm called criminal geographic targeting (CGT) to create a geo-profile, a two-dimensional probability surface that overlays on a street map and shows the most probable areas for the offender’s base (Rossmo, 2013). The geo-profile map normally uses color to represent probability. While this may initially look similar to a hot-spot map of the crimes, it is actually showing different information: where the offender is likely based rather than where they commit their crimes.
A geographic profile is used to prioritize suspects based on their address information. Suspects are investigated in the order of prioritization (MacKay, 1999). 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). There are a variety of investigative strategies that can be employed once a geographic profile has been prepared (Rossmo, 2013). 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).
A geographic profile can also be used to prioritize areas for directed police patrols or area canvasses. This strategy can be especially effective if the offender is operating during a narrow time period. The profile can be used to provide specific information to local area residents and neighborhood watch groups. Police may also want to use the profile to direct community mailings and/or conduct a media campaign (Rossmo & Velarde, 2008).
Finally, geographic profiles can be used for the placement of specific tools that gather information about people or vehicles that pass through an area, such as pole cameras or license plate readers. The data obtained from the placement of these tools can be reviewed and investigated by detectives.
The form of geographic profiling used by crime analysts and detectives is called Geographic Profiling Analysis (GPA). GPA training is currently available nationally and internationally through various universities and police agencies. In some states, such as California, GPA training is reimbursable to law enforcement agencies through state Peace Officer Standards and Training (POST) funds.
GPA courses provide an overview of the geography of crime, crime linkage, environmental criminology, and the operational aspects of geographic profiling for property crime. Students learn to identify offender behavioral patterns, analyze crime series for spatial-temporal patterns, and create maps and profiles using geographic profiling software. The training program includes lecture-style learning, group, solo and field exercises, hands-on activities, and evaluation/mentorship. Students who take GPA training are typically crime analysts and property crime investigators (Velarde, 2004).
Implementation of GPA by law enforcement is achieved through the training of agency personnel and the acquisition of geographic profiling software. Students are encouraged to complete profiles on as many cases as possible during their mentorship period, and to brief both command staff and officers/detectives as to the concepts of GPA and its potential use in the criminal investigative process (Velarde & Cooper, 2006).
The Irvine (California) Police Department (IPD) has used geographic profiling successfully for both local and outside agency cases. One case in which geographic profiling was effectively used by IPD is discussed below.
From 2010 to 2011, the City of Irvine experienced several arsons that IPD detectives believed were set by a single serial offender. The crimes were difficult to solve as there were no witnesses and most of the physical evidence had been consumed in the fires. In April 2011, IPD’s Crime Analysis Unit (CAU) was asked to provide an analysis of the series, including maps of the fires, a next-crime forecast, and a geographic profile.
The fires were occurring during the early morning hours in a residential neighborhood. The offender was burning car covers and flags, as well as using items of opportunity such as pizza boxes to set trash dumpsters on fire. The offender showed a lack of criminal sophistication; the crimes were close together, suggesting the offender was likely walking to the crime locations.
Using Rigel, Irvine analysts created a geographic profile for this case. The profile identified a highly populated residential neighborhood as the most probable area for the offender base, and analysts determined that this base was likely to be the offender’s home. Subjects living in the area whom had previously been arrested, had police contact, and/or were registered for arson were reviewed, however this failed to identify the offender.
DNA swabbing of unburned material was conducted, and the Orange County Sheriff’s Department DNA laboratory determined that three pieces of evidence contained genetic material from the same person, a female. This was the first physical evidence in the investigation and it was helpful because any suspect who was identified in the investigation could now be compared to the scene DNA.
A meeting with detectives and crime analysts was held to determine a case strategy. It was decided the best use of resources would be to try to intercept the offender as she hunted for her next target. The geographic profile outlined an interception area, and the crime forecast, based on descriptive statistics of the previous arsons, provided the most likely day of week and time of day for the offender’s future activity.
This information was used to deploy undercover officers. After several weeks of surveillance, one of the detectives saw a woman walking her dog as she entered a nearby elementary school during the early morning hours. When the detective saw smoke coming from behind a pillar at the school, he realized this woman was the serial arsonist. The detective put out the fire and followed the woman to her home where she was arrested. Her home was in the peak area of the geographic profile (marked by a blue square on the map).
While it does not directly solve cases, geographic profiling can spatially focus an investigation and help manage large volumes of information. It is well suited for crime analysts because of their experience using analytical techniques and generating maps. Through the acquisition of GPA training and geographic profiling software, a law enforcement agency can add an important tool to help in their investigation of serial crime.
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Velarde, L., & Cooper, J. (2006). Geographic profiling analysis: Implementation assessment and review. Unpublished manuscript, Irvine Police Department, Irvine, CA.
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