Victimology is, as the name suggests, the study of victims of crime. When attempting to catch the individual or individuals perpetrating a crime or series of crimes, the more the investigating officers know about the victim(s), the more likely they are to apprehend a suspect. This is especially the case when a serial or repeat offender is believed to be behind a number of similar or identical crimes. By examining a number of characteristics of the victim or victims, including physical appearance, lifestyle, criminal records if appropriate, types of people with whom the victim associates, types of activities in which the victims like to participate, and more, the investigators hope to identify patterns that will make it easier to track down the individual(s) responsible for the crimes.
A classic example of a high-risk victimology profile is one that involves drug abuse. A criminal preying on drug addicts and buyers of drugs (e.g., middle-class teenagers who are not addicts but are purchasing illegal drugs), for example, robbing the addicts and other buyers of cash and/or their newly purchased drugs, is targeting a select category of victims. All of the victims are purchasing drugs illegally. Police investigating the crimes will focus on suspects known to operate within the drug world, and who have an established record of preying on weaker, sometimes, very sick from withdrawal, individuals. The victims in this type of case are presumed by the criminal to be very reluctant to report their victimization to the police because their underlying actions are, themselves, illegal.
Another high-risk victimization profile might involve neighborhoods experiencing a rash of burglaries. All of the victims may reside in homes at the ends of the blocks on which they live. There may be a freeway on-ramp near the neighborhood. Houses located further inside the neighborhood are not being similarly burglarized. The pattern then, is of a criminal who specializes in home invasions and who only targets houses from which a quick escape is a simple matter of driving onto the freeway and departing the crime scene quickly. Targeting houses further inside the neighborhood are more risky for the criminal because of less immediately-available escape routes.
Rapists frequently operate according to a pattern -- referring here to "stranger rape" as opposed to "date rape," wherein the victim knows the perpetrator. A victimology profile may result in a noticeable pattern among the victims chosen for assault. They might all live alone, have certain similar physical characteristics, walk on the same trail through isolated woods at predictable times of day, and so on. By accumulating as much information as possible on the victims, the police are better able to identify these patterns that help lead to the arrest of a suspect.