11.1 Strategies and Tactics

A variety of police strategies and tactics can be used more effectively and efficiently with a geographic profile. While specific applications are best determined by the investigators responsible for the case in question, suggestions for effective approaches are presented below. Their development has been an interactive process involving detectives, profilers, and academics. Case examples are used to illustrate these strategies, but it should be made clear that the crimes were not solved by geographic profiling; they were resolved by the assigned investigators. Profiling plays a support role, the importance of which can vary, and it is only one of many techniques in the investigator’s tool box.

While the most common anchor point is the offender’s residence, some cases involve other bases of criminal activity. Clifford Olson used body dump locations near Agassiz Mountain Prison where he had once been incarcerated. John Collins hunted in the area around Eastern Michigan University where he was a student and summer employee. Aileen Wuornos based her “hitchhooking” from truck stops and freeway entrances in the town of Wildwood. Inmate records, enrollment and employee registries, and field checks were all potentially useful sources of investigative information in these cases. As important as residence is in structuring activity space, the value of business and institutional records should not be overlooked.

11.1.1 Suspect Prioritization

The geographic profile, in conjunction with a psychological profile, can help focus follow-up investigative work. The problem in many serial violent crime investigations is one of too many suspects rather than one of too few. Profiling

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can help reassess and prioritize hundreds or even thousands of suspects, leads, and tips.

The South Side Rapist in Lafayette, Louisiana, committed a series of 14 burglary rapes from 1984 to 1995. Detective McCullan Gallien refused to close the file, and requested a geographic profile which resulted in the identification of a neighborhood previously not considered. This was used as the basis for suspect and tip prioritization. One tip involved a sergeant with the Lafayette Parish Sheriff’s Department who both fit the FBI’s psychological profile and lived in the peak area of the geoprofile at the time of the crimes. DNA obtained from surveillance of the suspect matched samples from the crime scenes. The offender confessed, pled guilty, and was sentenced to life in prison. The geoprofile located the rapist’s address in the top 2.2% (0.5 mi2) of the hunting area. Figure 11.1 and Chapter 11 Colour Figures 1 and 2 show, respectively, the crime sites, jeopardy surface (top 20%), and geoprofile (top 15%) for this case. Residences of the offender are marked with blue dots in Colour Figure 2; his home during the main period of the attacks was the centre dot.

11.1.2 Police Information Systems

Additional investigative leads may be obtained from information contained in various computerized police dispatch and record systems. Such systems include computer aided dispatch (CAD) systems, records management systems (RMS), the RCMP Police Information Retrieval System (PIRS), and the like (Fowler, 1990; Rebscher & Rohrer, 1991). Offender profile details and case specifics can help further focus the search.

For example, police may be investigating a series of sexual assaults that have been psychologically profiled as the crimes of an anger retaliatory rapist. Such an offender is “getting even with women for real or imagined wrongs ...

the attack is an emotional outburst that is predicated on anger” (Hazelwood, 1995, p. 163). His rapes are often initiated by conflicts with a significant woman in his life and he will frequently select victims who symbolize the source of that conflict. A search of CAD data for domestic disturbance calls on the dates of the rapes to see which ones originated from the area where the geographic profile suggests that the offender most likely resides could produce viable suspects. This process is particularly powerful with police record systems integrated with geographic information systems.

Police agencies with computerized records containing description, address, and M.O. of local offenders can also use profiling information, including probable area of residence, as the basis for developing search criteria. Many departments have such files for specific types of criminals, such as parolees or sex offenders (Brahan, Valcour, & Shevel, 1994; Pilant, 1994; Skogan & Antunes, 1979). The latter commonly have nuisance crimes (e.g.,

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Figure 11.1 Lafayette South Side Rapist — crime sites.

loitering, trespassing, peeping, etc.) in their backgrounds, and the locations of their past offences may overlap with the present ones.

11.1.3 Task Force Management

Task force operations formed to investigate a specific series of crimes often collect and collate their information in some form of computerized major case management system, such as the British HOLMES or FBI Rapid Start programs (Federal Bureau of Investigation, 1996; U.S. Department of Justice, 1991b). Cases suffering from information overload will benefit from the prioritization of data and the application of correlation analysis (Keppel & Birnes, 1995). Geographic profiling can assist in these tasks through the ranking of street addresses, postal or zip codes, and telephone number (NNXs) areas.

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This process can also be linked to information available in CD-ROM telephone directory databases listing residential and business names, telephone numbers, addresses, postal or zip codes, business headings, and standard industrial classification (SIC) codes. The details of the specific task force computer database software, including information fields, search time, number of records, and correlational abilities, determine the most appropriate form the geographic profile should take to maximize its usefulness to the police investigation.

11.1.4 Sex Offender Registries

Violent sex offender registries are a useful information source for geographic profiling in cases of serial sex crimes (Popkin, 1994). By providing a list of addresses of known sex criminals, these registries can be used with a geographic profile to help prioritize suspects. The U.S. Violent Crime Control and Law Enforcement Act of 1994 “requires states to enact statutes or regulations which require those determined to be sexually violent predators or who are convicted of sexually violent offenses to register with appropriate state law enforcement agencies for ten years after release from prison,” or risk the reduction of Federal grant money (U.S. Department of Justice, 1994a).

Sex offender registries are powerful tools for monitoring and controlling criminal predators who, unfortunately, are more prevalent than is commonly believed. Washington State established the first such registry, and according to the Seattle Police Department Special Assault Unit, in May of 1995 the City of Seattle had a total of 859 registered sex offenders, an average of 10 per square mile. This figure does not include the 20% of released sex offenders who fail to register.

11.1.5 Government and Business Databases

Data banks are often geographically based and information from parole and probation offices, mental health outpatient clinics, social services offices, schools, and other agencies located in prioritized areas can also prove to be of value (it has been estimated that approximately 85% of our records contain an address). LeBeau (1992) discusses the case of a serial rapist who emerged as a suspect after police checked parolee records for sex offenders. Private businesses may also contain information of interest. In one case involving a series of sexual assaults, the criminal profile suggested the offender was likely a frequent user of pornography. An SIC code search for video stores on a CD-ROM telephone directory produced a list, which was then prioritized by address according to the geoprofile. Investigators could then use this information to focus on prioritized stores, showing composite suspect sketches, and checking frequent renters of adult video titles, knowing most people

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