List of Tables

Table 4.1 Modus Operandi Matrix Table 4.2 Case Variable Matrix

Table 7.1 Journey-to-Crime Research

Table 8.1 Criminal Predator Hunting Typology

Table 9.1 Holmes and De Burger Serial Murderer Typology Table 9.2 Serial Killer Characteristics

Table 9.3 Serial Murder Counts and Rates by State Table 9.4 Serial Murder Offender Data

Table 9.5 Serial Murder Victim Data

Table 9.6 Serial Murder Location Data Table 9.7 Crime Location Sets

Table 9.8 Crime Trip Distance Increase

Table 10.1 Crime Site Patterns and CGT Results Table 10.2 CGT Comparative Site Type Results Table 10.3 Urban Population Density

Table A.1 FBI Serial Killer Data Set

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List of Figures

Figure 4.1 Case linkage chart

Figure 7.1 Offender/target/environment Venn diagram Figure 7.2 Crime site search geography

Figure 7.3 Distance-decay function Figure 8.1 Raptor target pattern Figure 8.2 Stalker target pattern

Figure 9.1 Confirmed and suspected victim numbers by case Figure 9.2 Serial murder rates by state

Figure 9.3 Serial murder by day of week Figure 9.4 Distance to crime site

Figure 9.5 Mean logarithm of crime trip distance over time Figure 9.6 Crime trip distance mean standard deviation over time Figure 10.1 Journey-to-crime Venn diagram*

Figure 10.2 Vancouver robberies — Crime sites

Chapter 10 Colour Figure 1 Vancouver robberies — Jeopardy surface Chapter 10 Colour Figure 2 Vancouver robberies — GeoProfile Figure 10.3 GeoProfile confidence intervals**

Figure 10.4 CGT score distribution Figure 10.5 CGT operational performance Figure 10.6 CGT model learning curve Figure 10.7 Understudy training program

Figure 11.1 Lafayette South Side Rapist — Crime sites

Chapter 11 Colour Figure 1 Lafayette South Side Rapist — Jeopardy surface Chapter 11 Colour Figure 2 Lafayette South Side Rapist — GeoProfile

*From Rossmo, D.K. (1995b). Multivariate spatial profiles as a tool in crime investigation. In C.R. Block, M. Dabdoub, & S. Fregly (Eds.). Crime analysis through computer mapping (pp. 65-97). Washington, DC: Police Executive Research Forum. Used with permission.

**From Rossmo, D.K. (1997). Geographic Profiling. In J.L. Jackson, & D.A. Bekerian (Eds.). (1997b).

Offender profiling: Theory, research and practice (pp. 159-175). Chichester: John Wiley & Sons. Used with permission.

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Quotation

It is quite a three-pipe problem.

— Sherlock Holmes, in The Red-Headed League,

Sir Arthur Conan Doyle, 1891

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Interview the subjects, what they’ll tell you is, the thing that was really appealing to them was the hunt, the hunt and trying to look for the vulnerable victim.

— FBI Special Agent John Douglas; Mind of a Serial Killer, 1992, p. 3

This book is about geographic profiling. It is also about serial crime and violent predators. Human hunters are not common, but when they do strike, the public and the criminal justice system are significantly affected. Beyond the violence and tragedy of the crimes, these offenders generate tremendous fear in the community and demand significant resources from police, courts, and prisons. Most homicides and rapes are solved because there is a connection between the offender and the victim. Such a nexus is lacking in cases of stranger crime, and its investigation involves sifting through hundreds of suspects and thousands of tips. Consequently, police suffer from the problem of information overload. If we wish to enhance the investigative response to this type of random violence, it is important to expand our knowledge of serial predators and their hunting behaviour.

Geographic profiling is an investigative methodology that uses the locations of a connected series of crime to determine the most probable area of offender residence. It is applied in cases of serial murder, rape, arson, robbery, and bombing, though it can be used in single crimes that involve multiple scenes or other significant geographic characteristics. Developed from research conducted at Simon Fraser University’s School of Criminology, the methodology is based on a model that describes the criminal hunt. This book examines and discusses the spatial patterns produced by the hunting behaviour and target locations of serial violent criminals. Hunting behaviour refers to victim search and attack processes engaged in by an offender, and target

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locations are the various geographic sites connected to a crime series. Serial murder, for example, includes victim encounter, attack, murder, and body dump sites. The patterns and methods of offender hunting activity are analyzed from a geography of crime perspective. By establishing these patterns, it is possible to outline, through analyzing the locations of the crimes, the most probable area of offender residence.

The conceptual basis of this relationship is provided by the crime site selection model of Brantingham and Brantingham, who observe that individuals, including criminals, do not move randomly through their environment. The research led to an algorithm for predicting offender residence from crime site geography. The resulting computer system produces jeopardy surfaces — three-dimensional probability surfaces that indicate the most probable area of offender residence. These are displayed through the production of colour isopleth maps that provide a focus for investigative efforts.

Geographic profiling can be used as the basis for several investigative strategies, including suspect and tip prioritization, address-based searches of police record systems, patrol saturation and surveillance, neighbourhood canvasses and searches, DNA screening prioritization, Department of Motor Vehicle searches, postal or zip code prioritization, and information request mail-outs. It is important to stress that geographic profiling does not solve cases, but rather provides a method for managing the large volume of information typically generated in major crime investigations. It should be regarded as one of several tools available to detectives, and is best employed in conjunction with other police methods. Address information is an element of most record systems, and geographic profiling can be applied in a variety of contexts as a powerful decision support tool. Geographic crime patterns are clues that, when properly decoded, can be used to point in the direction of the offender.

For example, in the investigation of a series of over 20 rapes from 1988 to 1996 in St. Louis, Missouri, Detective Mark Kennedy employed both psychological and geographic profiling to prioritize a list of some 90 suspects for DNA testing. In addition to a residential focus, the geoprofile drew attention to the St. Louis State Hospital, and to what appeared to be likely commuting routes used by the offender. When the Southside Rapist was identified through DNA testing subsequent to a burglary arrest, it was found that he moved several times during the crime series. The geoprofile identified his residential area during his most active rape period — one home was in the top 2% (0.4 mi2), and the other, across the street from the St. Louis State Hospital, in the top 5.6% (1.2 mi2) of the hunting area.

The knowledge gained through research and experience of how and where criminal predators hunt for victims has both practical and theoretical implications. Geographic profiling is now an investigative support service

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offered to law enforcement agencies in cases of serious violent crime. It has been used by police departments in North America, Europe, and Australia. An ongoing study of the spatial patterns of criminal offenders is now occurring in several countries.

This book is designed to be a reference work on geographic profiling for both police practitioners and academic researchers. It covers investigative initiatives, crimes, and research studies in Canada, the U.S., and Britain. Its outline follows an order progressing from problem through to solution. Chapter 1 is an introduction. Chapter 2 discusses serial murder and the relevance of geography and distance for child murder and homicide investigation. Research on serial rape and arson is covered in Chapter 3. The general focus is on those aspects of serial crime related to offender hunting, crime location, movement, and geography. This discussion provides a context for the investigative problems and forensic behavioural science-based strategies brought up in Chapter 4. One of those strategies, criminal profiling, warrants its own examination in Chapter 5. Chapter 6 moves into the area of behavioural geography, and introduces concepts of importance for understanding the geography of crime research and theories presented in Chapter 7. Influences on criminal targets, including the hunt for victims, are discussed in Chapter 8.

Chapter 9 analyzes the spatial patterns of criminal predators, presenting original research findings from the study on the geography and targets of serial murderers conducted at Simon Fraser University. Chapter 10 focuses on the conceptual basis of geographic profiling, performance measures, relevant considerations, operational procedures, and the understudy training program. Chapter 11 presents several investigative strategies used with a geographic profile. Case examples illustrate these tactics, but it should be stressed that profiling only plays a support role. It does not solve crimes — that is the responsibility of the assigned investigator. There is also a discussion of a geographic profile based on the 19th-century murders of Jack the Ripper. Chapter 12, the conclusion, considers future research and where we need to go from here. The appendices contain research data and coding forms. A glossary explaining specialized terms and a comprehensive bibliography close the book.

One final note: depending upon the specification in the original source, both kilometres and miles are quoted in distance measures.1

1 The relevant distance conversions are: 1 kilometre = 0.621 miles, 1 mile = 1.609 kilometres; 1 metre = 1.094 yards, 1 yard = 0.914 metres; 1 centimetre = 0.394 inches, 1 inch = 2.54 centimetres; 1 hectare = 2.471 acres, 1 acre = 0.405 hectares; 1 square kilometre = 0.39 square miles, 1 square mile = 2.59 square kilometres.

© 2000 by CRC Press LLC