11.1.9 Mail Outs

Information regarding the offender can be mailed or delivered to those households and businesses located within the peak area of the geoprofile. This is accomplished through the geographic prioritization of postal or zip codes; postal workers in the appropriate letter carrier walks can then delivery the information packages at commercial rates, allowing thousands of premises to be covered for only a few hundred dollars. The purpose of this approach is two-fold. First, people are more likely to respond to an individualized request stating the offender resides in their neighbourhood than they are to generalized television broadcasts or newspaper stories. Second, this method generates high quality information as it comes from those individuals in a better position to know the offender from either home or work. Less focused methods often produce low quality responses and information overload problems. The mail-out tactic is viable only if the offender description information is sufficient and reliable; preferably, a suspect composite sketch is available. Personality details generated from a psychological profile can also be included.

11.1.10 Neighbourhood Canvasses

A thorough police canvass in the area where a victim was abducted, attacked, or dumped is a useful and proven investigative approach. Such efforts may also be directed within the neighbourhood of probable offender residence. Prioritized areas can focus door-to-door canvassing, interviews, grid searches, information sign posting, and community cooperation and media campaigns. Police departments have used this approach to target areas for leaflet distribution, employing prioritized letter carrier walks for strategic household mail delivery. LeBeau (1992) notes the case of a serial rapist in San Diego who was arrested through canvassing efforts in an area targeted by analysis of the crime locations. The Vampire Killer, serial murderer Richard Trenton Chase, was caught in the same manner after a psychological profile predicted he would be living near a recovered vehicle stolen from one of the victims (Biondi & Hecox, 1992).

Neighbourhood canvasses and grid searches sometimes cover vast areas. John Joubert left the body of his first victim, a young newsboy, in high grass beside a gravel road outside of Omaha (Ressler & Shachtman, 1992). This was 4 miles from where police located the victim’s bicycle, resulting in an extensive building-to-building search. A circle with a radius of 4 miles has an area of 50 square miles (130 km2). Methods to geographically prioritize searches of this size have obvious value.

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11.1.11 News Media

Investigative media strategies may use a geographic profile in attempts to generate new tips. Summary results or full profiles can be released, depending on the details of the specific case and the status of the investigation. Because of the risk of displacement, both spatially and temporally, this approach needs to be carefully considered. Factors such as the number of crimes, the rate of offending, the reliability of suspect descriptions, and the availability of other investigative initiatives must be assessed. Television shows, including CrimeStoppers, news broadcasts, and special crime programs are the most effective medium because of their visual nature and large coverage. Newspapers and magazines can also be used. Mainstream media might be supplemented with neighbourhood newspapers and community postings in key locations. Media strategies involving geographic profiling and surveillance activities should not be conducted at the same time as the former will hinder the latter. An optimal approach would first involve surveillance, followed by a media campaign.

During 1995, a series of 32 armed robberies targeting primarily insurance agencies plagued Vancouver, British Columbia. Three investigative strategies were predicated upon the geographic profile. First, a search was conducted of the Vancouver Police Department’s Records Management System for known robbery offenders, matching the criminals’ descriptions, who resided within the top 5% of the geoprofile. This failed to produce viable matches; it later turned out that neither offender had a previous conviction for robbery.

Second, a simplified geoprofile, displaying only the top 2% (0.7 mi2), was generated for patrol officers. Previous research found robbers usually return home after the commission of their crime; it was therefore suggested that in addition to responding to a crime scene after the report of a new robbery, patrol members should also search the most likely area of offender residence, with particular attention paid to logical routes of travel. This tactic also was unsuccessful; the offenders were using stolen cars and no reliable vehicle descriptions were ever obtained (the geoprofile was used by police units to search for stolen automobiles that might be “laid down” prior to a new robbery). The third tactic involved releasing the results of the geoprofile on television through CrimeStoppers. This approach was helpful in that the robberies immediately stopped. Detectives identified the offenders by reassessing their tips. The primary robber’s address was located within the top 1.5% of the peak geoprofile area. Figures 10.2, and Chapter 10 Colour Figures 1 and 2 show, respectively, the crime sites, jeopardy surface, and full geoprofile for this case. The residence of the offender is marked with a blue dot in Chapter 10 Colour Figure 2.

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11.1.12 Bloodings

During a sexual murder or rape investigation, British police may conduct largescale DNA testing of all men from the area of the crime (“How the DNA ‘Database,’” 1995). The first such case was the Narborough Murder Enquiry, when “all unalibied male residents in the villages between the ages of seventeen and thirty-four years would be asked to submit blood and saliva samples voluntarily in order to ‘eliminate them’ as suspects in the footpath murders” (Wambaugh, 1989, pp. 220-221). Close to 4,000 men from the villages of Narborough, Littlethorpe, and Enderby were tested during the investigation.

Because considerable police resources and laboratory costs are involved in such “bloodings,” British police conduct intelligence-led DNA screens in which individuals are prioritized based on proximity to scene, criminal record, age, and other relevant criteria (National Crime Faculty, 1996). In cases of serial crime, geographic profiling can further refine the selection process through targeting by address, or postal or zip code, resulting in more efficient and systematic testing procedures. Canadian police are also beginning to use this strategy. A series of 11 sexual assaults including a rape occurred within the space of just over a month in Mississauga, Ontario. The investigation by the Peel Regional Police resulted in 312 suspects. Combining the geographic and psychological profiles with description and interview information, detectives prioritized the suspects into groups and obtained DNA samples from the most probable individuals. The offender was identified in the first lot. He resided within the top 2.2% (0.03 mi2) of the area under consideration.

11.1.13 Peak-of-Tension Polygraphy

In presumed homicides with known suspects but no bodies, polygraphists have had success in narrowing down the search area for the victim’s remains through peak-of-tension (POT) tests (Hagmaier, 1990; see also Cunliffe & Piazza, 1980; Lyman, 1993; Raskin, 1989). Peak-of-tension polygraphy involves monitoring a subject’s reaction to photographs, objects, or maps, as opposed to answering verbal questions. A deceptive response to queries concerning the type of location where the victim’s body was hidden (e.g., cave, lake, marsh, field, forest, etc.) can help focus a search. Because POT tests often involve maps or pictures, their usefulness is enhanced when results are combined with a geographic profile.

11.1.14 Fugitive Location

In cases where the identity but not the whereabouts of a criminal fugitive is known, geographic profiling may be able to assist in determining probable

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hiding places. Sightings, purchases, credit or bank card transactions, telephone calls, cellular telephone switch sites, crimes, and other locational information can be used as input for the profile. This process is also applicable to extortion and kidnapping investigations.

11.1.15 Missing Bodies

In certain missing person cases that are suspected homicides, geographic profiling can help determine probable body dump site areas. In November 1993, a teenage boy was found shot dead in his parked car, and his girlfriend kidnapped, outside St. Antoine, New Brunswick. The murderer was identified through rifle ballistics but he disappeared before arrest. After unsuccessfully pursuing various leads and tips, the RCMP began to theorize that the missing female victim had been killed and the offender had committed suicide. Two searches by police and military teams of the rural Bouctouche region failed to find evidence of either body. A geographic profile was then prepared and it identified two prioritized search areas using techniques of path analysis, journey-to-crime estimates, and time-distance-speed calculations. A third search effort located effects of the offender in a river under a railway trestle, and the body of the female victim in a field; the former was found in the highest prioritized area of the geoprofile, and the latter in the second highest.

11.1.16 Trial Court Expert Evidence

While geographic profiling is primarily an investigative tool, it also has a role in the courtroom. In addition to analyzing the geographic patterns of unsolved crimes for investigative insights, the spatial relationship between the locations of a crime series and an accused offender’s activity sites can be assessed in terms of the probability of their congruence (Rossmo, 1994a). When combined with other forensic identification findings (e.g., a DNA profile), such information increases evidential strength and likelihood of guilt. The question of how to most appropriately quantify the weight of forensic identification evidence and rare trait possession is called the generalized island problem (see Balding & Donnelly, 1994). Geographic profiles can also be used as supporting grounds for search warrant affidavits.

On the cold winter morning of January 31, 1969, nursing assistant Gail Miller left home and walked to the bus stop to go to work (Karp & Rosner, 1991). She never made it. She was pulled into an alley, raped, and stabbed. David Milgaard, a 16-year-old youth from Regina, was later arrested, tried, and convicted of her murder. He was sentenced to life imprisonment but maintained his innocence throughout 23 years of incarceration.

In 1990, an alternative suspect surfaced. Larry Fisher was a serial rapist who lived in Riversdale, a block away from Miller’s bus stop, at the time of

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