Table of Contents
Overview of Appendices & Figures
Chapter 1: Geographic Profiling and Criminal Cases
How can Geographic Profiling Help in Criminal Case Processing?
Terminology of Geographic Profiling
Geographic Profiling in Criminal Cases
Measuring how much Geographic Profiling Contributes to Criminal Justice’s Success
Chapter 2: Theories of Travelling Behaviour Applied to Geographic Profiling
Typologies of Serial Offenders
Routine Activity, Rational Choice and Crime Pattern Theory
Behavioural Geography and Environmental Criminology
Travelling Habits by Offending Groups & Journey-to-Crime Conduct
Linking Crime Series by Modus Operandi: CCA - Comparative Case Analysis & CPA - Crime Pattern Analysis
Commuter and Marauder Models
Decay Functions in Geographic Profiling
Chapter 3: Geographic Profiling: How does it Work?
Implementation of Geographical and Criminological Theories in Geographic Profiling
Introduction into the Main Profiling Systems and Software and their Use
Criminal Investigation Programmes interacting with Geographic Profiling Systems 30
Case Studies: Examples for Practical Applications of Geographic Profiling in Police Work 32
Chapter 4: A Review on the Research Evidence on the Effectiveness of Geographic Profiling
Review of the Research Evidence on Geographic Profiling
Deficiencies in Geographic Profiling Techniques & Geographic Profiling Evaluation Methodologies
Human investigative skills vs. Geographic Profiling Software & Systems
Research Studies on the Efficacy of Geographic Profiling Systems
Conclusion on the Efficacy of Geographic Profiling Methods
Geographic profiling is an investigative methodology that tries to determine the most probable residence of a serial offender by a geographical analysis of the majority of the crime locations (Chainey and Ratcliffe, 2005, p.27).
This literature-based dissertation focuses on the efficacy of geographic profiling methods. It aims to find out if recent geographic profiling methods are really supportive to the criminal investigative process and to what extent they can contribute to solve criminal cases. As a structured literature review, it seeks to evaluate the relevant evidence about the use of geographic profiling in terms of criminal detection and practical investigative applicability. This is done by using other completed literature reviews or research reviews, including evidence from these reviews and, additionally, by reviewing the use of GIS (Geographic Information Systems) in recent criminal cases.
This dissertation provides an insight into recent applications of geographic profiling and a presentation of the main profiling systems. The results of this dissertation are achieved by evaluating and comparing data from empirical research and by reviewing the evidence about the efficacy of this technique.
The efficacy and relative success of the application of geographic profiling in criminal investigations are supported by presenting a range of criminal cases solved with the contribution of geographic profiling methods. On the other hand, deficiencies in geographic profiling systems and applications are shown by the presentation of several other independent studies.
Overall, this dissertation concludes that the evidence reviewed suggests that geographic profiling can contribute to solve criminal cases to a crucial extent, i.e. in cases of locating the offender’s base or predicting where the next offence location is to be found, and thus, this thesis gives strong support for the use of geographic profiling in criminal justice investigations. Finally, the evidence also points to a growing importance of predictive crime prevention applications of this technology in future.
Overview of Appendices and Figures
Table 1 Overview: Main Geographic profiling systems
Table 2 Overview: Supportive criminal investigative systems
Table 3 Main advantages and disadvantages of geographic profiling
Appendix 1 Example of a GIS probability surface
Appendix 2 The Commuter Model
Appendix 3 The Marauder Model
Appendix A Crime Analyst 2.0
Appendix B The Analyst’s Notebook 8
Appendix C The Analyst’s Workstation 8
Chapter 1 Geographic Profiling and Criminal Cases
This chapter will discuss the ways and possibilities of how geographic profiling as an investigative instrument can be used in order to assist in criminal case processing. Furthermore, it will introduce the main geographic profiling terminology to offer a better understanding of the topic as a whole, and it will try to give an idea of how the relative ‘success’ of the use of geographic profiling might be measured.
How can Geographic Profiling help in Criminal Case Processing?
Routine activities and pathways of every individual might affect his or her target selection as an offender (Beauregard et al., 2005, pp. 584). These traces can help in finding a perpetrator, collecting information about his/ her conduct in reference to his/ her offences, and finally, drawing conclusions where the offender’s residential location might be found. Hereby, theories in the field of environmental criminology or behavioural geography contribute to the development of geographic profiling as they provide the conceptual basis for geographic profiling (Chainey and Tompson, 2008, p.35).
Besides being a means for solving high profile cases, i.e. serial murder, rape, or burglary, geographic profiling also is thought to be a tool in preventing crime by identifying criminal hotspots, i.e. to install security techniques like CCTV cameras or enlarge patrols in a crime hotspot area. Its increasing meaning, mainly in terms of a use of crime maps as a support for the Government’s crime policy, was stressed at last year’s ‘National Crime Mapping Conference’ in London (University College London, 2010). Already in 2004, Bowers et al. proposed to focus on geographic profiling as a means for crime prevention by ‘ prospective hot-spotting ’ with the generation and evaluation of a ‘ risk surface ’ based on recorded crime data, especially in the field of burglary. The result of their paper suggests considerable advantages of such a method for the use of crime prevention (Bowers, Johnson, and Pease, 2004, pp. 641-642).
Crime mapping offers a tool to analyse a crime area’s before and after picture of the crime level (Chainey and Ratcliffe, 2005, pp. 27-28). Criminal hotspots are defined as relatively small areas which contain a disproportionate number of criminal offences (Block, 1990, cited in Rossmo, 2000, p. 125). The detection of these hotspots is done by cluster analysis. Crime does not spread evenly across space but is bunched in some areas and completely absent in others. Where crime heaps there are clusters which then are identified as criminal hotspots (Tabangin et al., 2008, p. 763).
Terminology of Geographic Profiling
Geographic profiling is a profiling strategy which uses pieces of geographical information of serial violent crime sites in order to determine the most probable location of offender residence (Rossmo, 2000, p.1). This strategy where crime relevant data are visualized and analysed is also called crime mapping; the technology by which this is done is GIS, the Geographic Information System, which by the help of software creates a geographic layer profile (‘ geoprofile ’), that is a multi-dimensional probability surface (‘ jeopardy surface ’ - see appendix 1) which is overlaid on a map of the crime area (Rossmo, 2000, p. 185 & Chainey and Rattcliffe, 2005, p.307). In order to translate information into spatially displayable GIS data they have to be edited in a process called ‘ geocoding ’ (Chainey and Ratcliffe, 2005, p.46). A common method to visualize crime data in forms of a continuous density surface is the ‘ kernel density method ’, or also the ‘ Kernel Density Estimation (KDE) ’ highlighting crime hotspots (Chainey and Ratcliffe, 2005, p. 156 & Weisburd et al., p. 175).
The commencement of the GIS technology can be indicated with the 1970. Only in the beginning of the 1980’s a further development on the computer market enabled the development of cost-effective GIS applications (Chainey and Ratcliffe, 2005. p.2). In 1995, McDonnell and Kemp defined GIS:
- ‘ GIS is a computer system for capturing, managing, integrating, manipulating, analyzing and displaying data which is spatially referenced to the Earth. ’ - (Chainey and Ratcliffe, p. 38).
Chainey and Ratcliffe add that GIS makes it possible to layer crime data with base maps and other geographical information. In spatial analysis, layers are first integrated and then analyzed against each other. The spatial representation of objects can be in points, lines and polygons (2005, pp. 38-42).
The common paths and routes everybody travels routinely may lead to or even determine certain decisions related to a criminal action. According to the research by one of the leading figures in the development of geographic profiling, Canadian Police Detective Kim Rossmo, geography plays an important role for the offender for an offender’s base is his/her most important place. The base or also anchor point describes the place from which the perpetrator executes his crimes and - if he does so - plans them. Besides the offender’s home this can also be his/her working place or a friend’s home (Rossmo, 2000, p. 91). These locations also function as a kind of secure retreat. In forms of a circle around the base there are the activity space (the inner circle) and the awareness space (the outer circle) within which individuals, offenders as well as other individuals, move routinely, followed by an unfamiliar area. All of these areas are influential to the behavioural and decisive process of every individual. In the definition of activity space by Jakle, Brunn and Roseman from 1976, activity space contains those areas that include an individual’s habitual geography, which means routinely visited places and their connecting routes (Rossmo, 2000, p. 90), whereas the awareness space describes all the locations which an individual has knowledge about, according to Clark, 1990 (cited in Rossmo, 2000, p. 90)
Additionally to the term ‘awareness space’, Brantingham and Brantingham (1984) also mention the ‘opportunity space’ which is crucial for a crime (cited in Canter and Youngs, 2008, pp.93-94). In this context, opportunity space corresponds to the final element of preconditions which are necessary to make a crime possible according to the routine activity theory. The next section will introduce these issues more detailed.
Geographic Profiling in Criminal Cases
The first and foremost requirement for geographic profiling is the occurrence of a serial crime as only in a series of offences enough data can be gathered to Viola Abelius - Page 11 - May 2011 evaluate them in a geographical manner. Different crime locations are vitally necessary to find an overlap for further examination. As Keppel and Weiss (1994) put it, ‘ the more information known regarding times and locations of the crimes, the greater the likelihood the case will be solved ’ (Rossmo, 2000, p. 33). In the first place, a series of crime requires the same perpetrator to commit more than one offence. The process by which this is ascertained is called CCA, Comparative Case Analysis, a method to compare crime data and then link crimes by Modus Operandi, for example (Rossmo, 2000, pp.53-54) or, as Canter and Youngs call it, by ‘ similarities in behavioural domains ’ (2008, p. 202).
In criminal case profiling relying on geographic profiling methods, the circle model with home or base, activity space and awareness space provide the basis of calculations for spatial analysis regarding the offender search whereby the activity space is the place most likely for crimes to occur. Centred around an offender’s residence there is a buffer zone which marks a kind of safety distance zone for the offender and thus is not a preferred area for criminal activities (Young, 2006) because the risk of being detected appears to be much too high (Canter and Youngs, 2008, p. 9).
The geographic profiling method uses these underlying geographical assumptions to evaluate, by use of mathematical algorithms (Paulsen, 2005, p. 308) and by an analysis of the several offence locations, the spatial behaviour of the offender (his/her ‘ journey-to-crime ’ conduct) to finally determine a narrow radius in which his/her base or residence can then be predicted. The journey-to- crime conduct is characterized by certain crime trip patterns (Rossmo, 2000, pp. 99-101) which again are motivated by the spatial behaviour of the individual offender, whereby certain similarities concerning the distance between offender residence and location of offence were found in a range of studies (Rossmo, 2000, pp. 98-99). In the prediction of the serial offender’s home base an interaction of several databases and geographic profiling systems is necessary. The criminal data gathered at the location of crime can be matched with further databases like, for example, the FBI Combined DNA Index System (CODIS) which consists of a forensic index for unsolved crime and the convicted offender index (Rossmo, 2000, p. 55). So, the more data can be gathered and aligned the more precise the prediction can be. In chapter 3 the different databases and profiling systems will be introduced and their interactions illustrated.
Measuring how much Geographic Profiling Contributes to Criminal Justice’ s Success
‘Success’ is hard to determine, particularly the relative success of GIS compared to other techniques, or relative to other techniques. Systematic reviews, like for example the Campbell Systematic Review ‘Geographic Information Systems and their Effects on Police Efficacy’ (2010), which will be discussed in chapter 4, try to answer very specific research questions by including experimental research, with RCTs (Randomised Controlled Trials). Other ways of measuring success might include: (1) the number and percent of solved cases; (2) the number and percent of correctly calculated offender home bases; (3) an expeditious operation within a criminal investigation, thus GIS as a time-saving application.
There are three other crucial points to decide if a profiling method is successful and hence helpful for the investigative work of the police: first of all, a profiling method must be easily applicable for the staff using it, secondly, it must be timesaving and cost-efficient and finally, sufficient police staff must be trained in the techniques. Concerns about smaller police agencies which are not able to provide neither the necessary technical equipment to implement geographic profiling systems nor the financial or the staff capacity are being expressed by Snook et al (Snook, Taylor, and Bennell, 2004, p. 118-119). The cost-benefit calculation therefore is an important clue to the question if geographic profiling systems are the solution for an efficient crime tackling in the 21st century.
Chapter 2 Theories of Travelling Behaviour Applied to Geographic Profiling
This next chapter will introduce the most common theories of the travelling conduct of people in general and offenders in particular to show how the mobility usage of each individual might affect his or her decision-making, especially with regard to criminal activities. In this context, the routine activity, rational choice, and crime pattern theory are explained. Also, a typology of serial offenders will be presented because geographic profiling usually is applied in cases of serial offences.
Typologies of Serial Offenders
In 1983, the U.S. Senate titled a Congress on the issue of serial murder:
- ‘ Patterns of murders committed by one person, in large numbers with no apparent rhyme, reason, or motivation ’ - to describe the phenomenon of serial killing.
To classify serial offenders, the FBI typology appears to be the most functional one:
- ‘ Serial murderers are involved in three or more separate events with an emotional cooling-off period between homicides. [ … ].’- (Rossmo, 2000, pp. 6-7).
Holmes and Holmes (2002) have presented serial offender typologies under two aspects, first by different offender groups, such as serial arsonists, murderers, rapists, etc., and, secondly, they have shown the different typological aspects of the organized and the disorganized type of offender. All of these typologies are of use for profiling in general and geographic profiling in particular.
The main characteristics of the disorganized offender are: below-average intelligence, socially inadequate, low-birth order, and unskilled worker, most of the time living alone. Opposite to this, the organized type’s characteristics are: high intelligence, socially adequate and sexually competent, high-birth order, and living with a partner. Furthermore, the organized type is in a controlled mood when committing his crime. These behavioural traits are reflected in how the two types leave behind their crime scenes (Holmes and Holmes, 2002, pp. 72-78).
Typologies by offending groups show a range of distinctive features. Based on broad research, Holmes and Holmes point out that different groups of serial offenders like arsonists, rapists or murderers show varying kinds of geographical behaviour, they have a different family and job background and derive from different social classes (Holmes and Holmes, 2002, pp. 90-104 & 142). Hereby, serial killers show quite specific features: They tend to be male, white, aged from 25-34 years, intelligent, charismatic, charming, and interested in police’s work. Furthermore, serial killers tend to select their victims on the basis of certain characteristics, may they be physical, personal, or a combination of both. That is to say that every serial murderer has a kind of ‘victim ideal’. (Holmes and Holmes, 2002, pp. 110-117 & 132).
Additionally, each offender has his/her own ‘ signature ’, that is a typical way of committing the crime by which he/ she also can be identified in a series of crime and so help the investigator to choose the most appropriate method of investigation. But, it is fundamental to notice that all these categorizations are only rendering assistance to roughly allocate the offender to a certain group but a generalization for all offenders must be strictly avoided as each offender is an individually acting person not comparable to another (Cudrig, 2006, p. 16 & Musolff and Hoffmann, 2002, p. 115).
Routine Activity, Rational Choice and Crime Pattern Theory
Three major criminological theories are relevant for the better understanding of geographic profiling: routine activity theory, rational choice theory, and crime pattern theory. Theoretically, for a crime to occur three premises must be fulfilled: victim and offender must meet at the same time at the same place and the opportunity for a crime must be given which includes the absence of a capable guardian against the crime.
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