GEOGRAPHIC PROFILING

When entering the data for analyzing the geographical patterns, the principle elements involved are:

• Distance
• Mental Maps
• Mobility
• Locality demographics

Richard Trenton Chase
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Central to the approach is the idea that there is a difference between perceived distance and actual distance, and certain things influence how this disparity can affect the commission of a crime. Perceptions of distance vary from one person to another, and how distance is perceived can be influenced by such things as availability of transportation, number of barriers (bridges, state boundaries), type of roads, and familiarity with a specific region. The fact that Richard Trenton Chase, the notorious "Vampire of Sacramento," did not have a car meant that he had to take into account how far it would be to walk from a crime site back to his home. The fact that Ted Bundy did meant that he could travel across the country if he wanted to.

Another significant factor in geographical profiling is the concept of a mental map. This is a cognitive image of one's surroundings that is developed through experiences, travel routes, reference points, and centers of activity. The places where we feel safe and take for granted are within our mental maps, and the same holds for offenders. As they grow bolder, their maps can change and they may then increase their range of criminal activity.

Some criminals are geographically stable (stay in a certain region) and some are transient (travel around). Whether they tend toward stability or mobility depends a lot on their experience with travel, means for getting places, sense of personal security, and predatory motivations. Ted Bundy, for example, traveled from the Pacific Northwest to the Midwest and finally to Florida before finally being stopped for good. A cocky man, he admitted to killings in ten different states.

The mental map may also be dependent on whether the killer is a hunter, stalker, or has some other mode of attack, since the type of approach used on a victim also has a relationship to the location of the killer's home base.

Rossmo lists the relevant offender styles as:

• Hunter (searches for a specific victim in home territory)
• Poacher (travels away from home for hunting)
• Troller (opportunistic encounters while occupied in other activities)
• Trapper (creates a situation to draw a victim to him)

Any of these types might attack the victim upon encounter, follow a victim before attacking, or entice the victim toward a more controlled area, and these, too, play a part in the calculations.

In general, geographical profiling asks the following types of questions:

• Why did he pick his victims from a particular neighborhood?
• Why did he pick the dump site (in the case of murder)?
• What route must he have used?
• When did he use this route?
• How is the route generally employed by others?
• What do the attractions of this route say about him?
• In the case of a series of crimes, what are the geographic patterns?
• Are there escape routes?
• Was the area where the victim was taken appropriate for predatory activities?
• Was the victim attacked in the same place that he or she was encountered?
• Was the vehicle used in the attack also dumped somewhere?

Profilers like Rossmo believe that plotting the travel routes of serial offenders makes the offender's mobility more predictable. The more he offends, the more confidence he gains and the more his crime area tends to expand. That means that the initial acts will in all likelihood be closest to where the offender lives. Even Bundy began in his own neighborhoods. That's why Rossmo believes that geographic profiling is locating the killer: it focuses on where he lives and travels rather than focusing on where he might commit his next crime.

There are some geographic profilers who are so confident in this approach that they believe it supercedes the methods used in psychological profiling. Let's look at what one of the leading authorities has to say.