Geographic Profiling Developed by Kim Rossmo as his Ph.D dissertation at Simon Fraser based up the work of the Brantinghams Based on the assumption that crime locations are not random

Geographic Profiling Definition: an investigative technique used to determine the most likely location of a criminal’s residence based upon the geographic location of crime sites Suitable crimes: Serial offences (murder, rape, arson, bombings) Predatory crimes (child abduction, sexual homicide) Multiple location crimes (credit card usage, property crimes) So here we have the official definition of geographic profiling, which I gave you a few moments ago. Geographic profiling is an investigative technique used to determine the most likely location of a criminal’s residence based upon the geographic location of crime sites. As a crime fighting technique, it is appropriate for serial offences such as murder, rape, arson, and bombing attacks. It can be used for predatory crimes such as child abduction and sexual homicide. And it should be used for crimes committed in multiple locations such as fraudulent credit card usage and property crimes.

Geographic Profiling Based upon principles of: “least effort” Routine activity Distance decay Beyond the assumption that the location of one’s crime is not randomly selected, geographic profiling is also based on the following three principles. First, “least effort”. In most cases, criminals are not going to go to a lot of effort to move out of their area. They are going to stick with what they know and the distance they are willing to travel is very limited. Of course, there will be variations. Older offenders will travel further than younger offenders. Bank robbers will travel further than burglars. But the important thing to remember is that humans don’t go any further than they have to in order to accomplish their goals. Not even criminals. The second principle is routine activity. Criminals scope out potential victims during their routine activities. In fact, one of the tactics used by authorities to solve murder cases, for example, is to connect the victim and the suspect in terms of their routine activities. Do they get coffee from the same coffee shop? Do they get on the bus at the same stop? Geographic profiling assumes that criminals plan their attacks during their daily routine activities. The final principle is distance decay. The study of location can be very complex, and I am probably oversimplifying things here, but generally speaking, the further away you get from where the crime took place, the further you are getting from the criminal’s home or workplace as well. Because the scene of the crime and the criminal’s home or workplace are going to be very close together. So beyond the idea that criminals don’t travel far from home to commit their crimes, there is also this idea that the probability of where to find the criminal declines or decays the further away you get from the scene of the crime.

Requirements for Geographic Profiling Complete familiarity with the case file Examination of the crime scenes (minimum of 5 crimes) Interviews with investigators and witnesses Study of area maps Analysis of neighborhood demographics for both the abduction site and body dump site Computerized analysis So how is geographic profiling used? Well, Rossmo developed a software program that is now used by the RCMP, the FBI, and other crime-fighting organizations all over the world. Rossmo, or any other officer, would start by familiarizing himself with the case file. He needs to know all of the details of the case. And he needs to see all of the crime scenes, which is why you saw Rossmo getting out of that military helicopter at one of the Washington sniper crime scenes. He still has to do legwork at the scene of the crime. He needs to interview investigators and witnesses. So he is still using all of the traditional investigative techniques. But then, he will start to study maps, and he will assess the demographics of the neighbourhood where the crime took place and any secondary sites, such as where a body is dumped. And once he has analyzed all of this material, he inputs the details from the interviews, the crime scene, and the demographics into his computer program. Remember, as we learned in our study of methodology, computer simulations and computer programs are only as good as the information that we feed into them. So geographic profilers have to be careful to input all of the important variables and to do so correctly.

Geographic Profiling Profiling software then produces a probability map to show the most likely residence locations for the suspect. Red indicates the most likely area to search. The profiling software then produces a probability map, using a mathematical formula, to show the most likely residence locations for the suspect. Red indicates the area where you will most likely find your suspect. So as you move from the purples on the outside of the map to the reds on the inside of the map, you are increasing your probability of finding the criminal. So this map tells police to go to the red area and to focus their investigative efforts in that section of the city. To give you an example, maybe the police should start looking at who got parking tickets in that area of the city. They can’t look at parking tickets issued everywhere, but they can look at tickets issued in one small area of the city. And this technique has worked in the past. The Son of Sam was caught in Brooklyn by looking at parking tickets. They found this man had received a ticket and had no obvious reason to be in Brooklyn.

Geographic Profiling Once the area has been located, traditional investigative techniques are used: Address-based searches of police records Increased patrols Door-to-door searches/questioning Tip prioritization DNA screening prioritization Once the red area has been identified, police will return to their traditional investigative techniques. They will do address-based searches of police records. So they will look at suspects previously known to police who happen to live or work in that area of the city. They will increase police patrols in that area of the city. You might even put undercover officers in the area. Perhaps you will have an officer dressed as a homeless man or an officer pretending to fix a telephone pole so that the police surveillance is not so noticeable and there is no risk of scaring away your suspect. You can also do door-to-door searches or door-to-door interviews. You couldn’t possibly do this for every house in the whole city, but you can do it in this significantly smaller area. And having narrowed down your area of suspicion, you can now prioritize the tips that you receive from the public. You can ignore the silly tips that involve the wrong area of the city. For example, “my boyfriend came home with another girl’s number last night, so he must have committed your crime!” You’re able to ignore bizarre tips like this and to focus your time and manpower on the tips that are now considered more useful. And the same can be done with DNA screening. It’s costly and time-consuming to get samples of DNA. But if you’ve narrowed down your search to a specific area, then you’ve narrowed down the number of DNA samples that you will need to process. So you bring people in for questioning, and you offer them a coffee or a cigarette, and you get a saliva sample from the mug or the cigarette butt and you run your DNA comparisons. As a result of your geographic profiling, you are bringing in fewer suspects and therefore are having to do less DNA screening.