Colin Johnson, who used geographic profiling in the hunt for the M25 rapist Nick Wilson and Matt Rainwaters

This article was taken from the November 2014 issue of WIRED magazine. Be the first to read WIRED's articles in print before they're posted online, and get your hands on loads of additional content by subscribing online.

In August 1996, Kim Rossmo, a detective inspector from the Vancouver Police Department (VPD), was contacted by a UK police task force called Operation Lynx. The task force involved police officers from three counties -- Leicestershire, West Yorkshire and Nottinghamshire -- who were all searching for a man responsible for five abductions, rapes and violent sex attacks over the previous 15 years.


The most recent had happened in July 1995, at around midday, in a multistorey car park in Leeds, when a 22-year-old student was grabbed while getting into her car. The assailant covered her eyes with superglue, tied her up and sexually assaulted her. He cut himself, leaving a trace of blood in the car. Six months later, forensic scientists matched the DNA in the blood with DNA found at a crime scene in Nottingham in May 1993, when a 23-year-old woman was abducted at knifepoint and raped. Shortly after, the police linked the attacker to three more rapes that had occurred between 1982 and 1984 in Bradford, Leeds and Leicester.

It led to one of the biggest manhunts in British history: the area of the crimes and related incidents was 7,046km<sup>2</sup> and the police had 12,122 suspects. Operation Lynx needed Rossmo's help.

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Rossmo had developed geographic profiling, a method of tracking serial criminals which used data about the location of the crimes.

The method often relied on a crime-analysis program called Rigel which estimated the area where an offender lived based on the crime locations. Rossmo, who had founded VPD's first geographic profiling unit in 1995, had a growing reputation after he helped to solve a number of murders and rapes, including some in the UK. "Lynx was a test case to see how those methods could be used here," says Spencer Chainey, principal research associate at the Jill Dando Institute of Security and Crime Science at University College London. "After that, pretty much every serial criminal case you read about in the media, from the murder of Milly Dowler to the case of the Suffolk strangler, has involved geographic profilers." "Initially, I thought that geographic profiling would be of limited use there," Rossmo recalls. "I only had data related to the five rapes, which isn't enough for an accurate analysis." Apart from the DNA taken from the sample of blood, the police also had a partial fingerprint. The print, however, was too small to be matched using automatic fingerprint recognition, a system that matches samples against a database of convicted criminals.


By the time Rossmo visited the crime sites in May 1997, investigators had made a further connection: a stolen blue Ford Cortina, which the attacker used during the second rape. Inside the glovebox, the rapist had found a credit card, which he had then used around Leeds to make a number of purchases, including a £20 Parker pen, a video game called Scramble, a shirt, alcohol and cigarettes. "All routine purchases that you would normally make near where you live," Rossmo says. "This made me focus even more on Leeds."

Using the locations of the Leeds crimes and purchases, Rossmo calculated a geographic profile using Rigel. It highlighted two areas, including the Millgarth and Killingbeck districts. Both of those districts had police stations, so the investigation initiated a manual search for a fingerprint match at the two locations.

Kim Rossmo, the head of the Centre for Geospatial Intelligence and Investigation at Texas State University, in Austin, Texas, August 2014 Nick Wilson and Matt Rainwaters

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The painstaking search went on for months and the investigation began to run out of steam. There was no match at Millgarth. But, on Friday, March 19, 1998, after 940 hours spent sifting through more than 7,000 fingerprint records, an analyst found a card at Killingbeck that matched the partial fingerprint from the Nottingham rape. The suspect was Clive Barwell, a lorry driver, married with three children. His fingerprints were on police records because he had been in prison from 1989 until 1995 for robbing security vans with a shotgun. "He was officially listed as in custody during the rape in Nottingham," says Rossmo. "But he had been given an unauthorised and unrecorded pass for the weekend in which he committed the rape."


Barwell lived in Killingbeck. His mother lived in Millgarth, the other area highlighted by the geographic profile, and he used to visit her regularly. A DNA test provided a match and, in October 1999, Barwell pleaded guilty in court. He was sentenced to eight life terms. "The offender's residence was in the top three per cent of the geoprofile," Rossmo says. "Without any prioritisation, all else being equal, the offender would have been found, on average, in the top 50 per cent of the area. During our last meeting, the detectives told me that the investigation was winding down. If the prioritisation was wrong, it was unlikely Barwell would have been identified in time."

Shortly after Operation Lynx, the UK's National Crime and Operations Faculty sent one of its detectives to study under Rossmo and learn his techniques. In 2000, the organisation opened the first UK geographic profiling unit. Today, geographic profiling is used in tens of top-tier crimes every year in the UK, not only in high-profile cases but also ones as diverse as a series of arson attacks on wheelie bins and houses in Chester-le-Street, near Durham, and in the case of a man responsible for 23 knife-point robberies in south London.

Case 01 Operation Lynx

In the years since Operation Lynx, Rossmo's innovative methods have increasingly become part of criminal investigations around the world. More than 725 people from 350 police agencies, including the Royal Canadian Mounted Police, the FBI, the Bureau of Alcohol, Tobacco, Firearms and Explosives and the UK's National Crime Agency, have been trained as geographic profilers. Recently, Environmental Criminology Research Inc (ECRI), the company cofounded by Rossmo, has sold Rigel to Shandong State police, the first crime agency in China to buy the software. "Geographic profiling a serial criminal makes a lot more sense than the more traditional psychological profiling," says Colin Sutton, the former senior investigating officer of the Metropolitan Police Murder Squad who led the investigations to convict Levi Bellfield, the notorious killer of Amelie Delagrange, Marsha McDonnell and Milly Dowler. "I fail to easily recall an instance where psychological profiling has assisted an officer in solving a series of serious crimes. Whereas geographical profiling is a much more exact science that can help target resources and target our enquiries into a specific place."

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'Geographic profiling a serial criminal makes a lot more sense than the more traditional psychological profiling'

Rossmo's methods have changed the way serial crime is tackled.

They're disrupting how we address a vast range of problems, from epidemics to terrorism. Rossmo, who now heads the Centre for Geospatial Intelligence and Investigation at Texas State University, has worked with US Border Control, using Rigel to identify illegal-immigration patterns. Military analysts have used geographic profiling to detect enemy bases from the locations of IEDs and rocket-propelled grenade attacks in Iraq and Afghanistan.

In 2007, Rossmo visited Istanbul and Ankara, Turkey, where he inspected the sites associated with the assassination of a former minister of justice in the capital. "People usually say terrorists don't have spatial patterns,"

Rossmo tells WIRED. "That's nonsense. We found strong geographic patterns in the terrorists' networks and we can use the ideas of geographic profiling to evaluate counter-terrorism intelligence."

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With Steve Le Comber, a mathematician at Queen Mary University in London and one of his closest collaborators, Rossmo recently used Rigel to find the home of Otto and Elise Hampel, a couple who secretly distributed anti-Nazi propaganda during the second world war. "The secret services found it so interesting that they have asked us to publish a report in one of their internal journals," says Le Comber. "The journal is confidential so not even we, the authors, have access to it."

It was also with Le Comber that Rossmo discovered one of Rigel's most surprising applications. "We applied it to biology, out of curiosity," says Le Comber. "I didn't really think it would work but it does. You can apply it to, say, bat foraging and invasive species. Its most interesting application is in epidemics. We tested it on an outbreak of malaria in Cairo and managed to find the breeding sites of the mosquitoes."

Case 02 Irvine City

Le Comber is working with Public Health England and the Department of Environment, Food and Rural Affairs, using Rigel to fight infectious diseases. The applicability of geographic profiling to the natural world is perhaps a testament that there are few patterns more universal than the way humans and animals move, search and hunt. Our relation to geography, with its reliance on routine and the principle of least effort, is fundamentally predictable. That's why looking at the geographical component of a crime can be a crucial part of a strategy to solve it. A geographic profiler might not solve cases -- only a confession, a witness or physical evidence can prove guilt -- but when you have thousands of suspects and very little data, as in the case of Operation Lynx, who better to ask than someone like Kim Rossmo, who knows the geographical habits of serial criminals and can tell the police where to focus their research?

Rossmo is in his late 50s, with thinning hair, neatly trimmed stubble and a friendly, earnest manner. On his last year in high school, he was asked to take his final maths exam in the second week of class and obtained a perfect score. While at university, he took a part-time job as a private investigator because, as he puts it, he needed the adrenaline rush. He joined the Vancouver Police Department in 1978. In 1995 he says he became the first police officer in Canada to obtain a PhD, which he completed at the School of Criminology at Simon Fraser University in Vancouver. It was at Simon Fraser that he became interested in the ideas of criminologists Patricia and Paul Brantingham, who introduced him to the new field of environmental criminology.

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For environmental criminologists, crime locations are important clues -- where the criminal and victim first met, where the abduction took place, where the murder happened, where the body was dumped. "When the police set up a crime-scene investigation, the focus is usually on finding evidence, such as DNA and fingerprints," Rossmo says. "We tend to forget that for a crime to have occurred the offender and the victim had to come together in time and space."

The Brantinghams' theory was applied to aggregate crime patterns of hundreds of offenders, but soon it dawned on Rossmo that their ideas could be reversed and applied instead to individual crimes, in particular to serial criminals. Around 75 per cent of homicides in Canada are solved, essentially because murder victims are usually attacked by someone they know: a spouse, a partner, a family member, a work colleague. Serial killers are a different problem, because the criminal usually has no previous relationship with their victims. That lack of connection makes serial crimes more difficult to solve. "The question I asked was, if we know the location of the crimes, what can we say about where the offender lives?" says Rossmo. "Take one of those rotating lawn sprinklers: it's quite difficult to predict where the next drop of water is going to fall.

On the other hand, if you wait for a lot of drops of water to fall, it's relatively easy to work out where the sprinkler is from the pattern of the drops. That's the analogy."

Rossmo studied serial murder and quantitative geography and animal foraging patterns, among other topics. "What primarily determines where a criminal offends is where he goes when he's not offending," he explains. "Those areas make up the criminal's comfort zone and, like most people, that's where they spend most of their time. Crimes happen when they find potential targets, a victim or a shop to rob, within that area. That's why most crimes occur close to where he lives or works, an area where he grew up or previously lived, where they work or even where a relative lives."

In other words, victims are not primarily chosen because of who they are but because they happen to be in the wrong place at the wrong time.

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According to Rossmo, most crimes take place close to the offender's home, often within a kilometre. As you move further away from their home, the probability they will offend drops off, a pattern called "distance decay". However, criminals are also less likely to offend very near their home, partly to protect their anonymity, an area called the "buffer zone". The balance between these two tendencies dictates where crime is most likely to occur.

There are some variations to this pattern: adult offenders tend to travel further than do juvenile offenders; robbers tend to travel longer distances than do burglars; body dumpsites tend to be further from the killer's residence than from the sites they meet their victims.

Rather than trying to calculate the exact location of the offender's home, which was unrealistic, Rossmo decided to devise a mathematical algorithm that, given a map with various locations associated with a series of crimes, could calculate the most probable location for the offender's residence. He had a breakthrough in 1991, during a research project in Japan about community policing. "I was on the bullet train heading south of Tokyo, looking out of the window, and a formula jumped out," Rossmo recalls. "I grabbed a napkin and wrote the equation down."

The algorithm, called criminal geographic targeting, was later developed into Rigel. To use Rigel, a geographic profiler first enters the crime locations using a computerised map. The software then lays a 40,000-pixel grid over the area of the crimes. For each pixel, the software adds a probability function that mathematically expresses the interplay between the buffer zone and the distance decay. The function, according to Rossmo, looks like "a volcano with a caldera". Rigel then adds the probabilities for all the crime locations, outputting a probability surface across the map.

The map is visually similar to a topographic map, but instead of elevations, each point depicts the likelihood the offender is based there. The peak of that topography represents the point where the serial killer is likely to begin his hunt from, in most cases his home.

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In 1998, soon after completing his PhD, Rossmo received a request from the Lafayette Police Department in Louisiana to help identify a criminal known as the South Side Rapist. Since 1984, a man wearing a scarf across his face had assaulted 14 women in their homes. The police didn't have much apart from DNA samples from six of the sites and thousands of suspects.

When Rossmo is preparing a geographic profile, he can spend hours at crime sites. He also typically goes back and forth between the various crime scenes in different directions and at different times of the day, walking or driving, to understand how one location connects to another. He gets weather data from the dates of the crimes and checks for nearby bus stops, subway stations and bars. "Computers can do a lot but the analyst creates the profile," says Rossmo. "When a geographic profiler works a case, it may take a week to do the profile but only half a day on the computer. The rest is reading reports and understanding what's going on. What's the hunting style of the criminal? How did the offender know about the location? What was his geographical modus operandi? In every case, you need to know the situation from the offender's perspective."

In Lafayette, Rossmo and lead investigator McCullan Gallien walked the streets for three days, studying the sites. "There were homes in the projects, in rich neighbourhoods, apartments, and single-family dwellings," says Rossmo. "He had a large mental map, which means he was comfortable in a wide range of environments, so I'm thinking he could be a taxi driver or delivery guy. Also, for pretty much every house I had to take two steps off the sidewalk and I could be at a window."

To Rossmo, this suggested someone who's driving through neighbourhoods at night, peeping in windows and choosing his targets with care. "Some offenders are very good at reading environmental clues," he says. "One offender, for instance, told me that he liked houses with cats because that suggested a woman. It's a very effective way of choosing targets."

Rossmo generated a geographic profile which narrowed the number of suspects to about a dozen. All were cleared after taking a DNA swab test. The police then got an anonymous tip about Randy Comeaux, a sheriff's deputy, whom Gallien knew personally.

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Comeaux's address was in the top eight per cent of the geoprofile, which was not a great hit. But Gallien reasoned that the geoprofile wasn't based on where the offender was living today, it was based on where he was living at the time of the rapes, so he checked the personnel records. Comeaux's old address was in the top one per cent of the geoprofile, an area less than 1.3km<sup>2</sup>.

Gallien used a discarded cigarette butt to extract Comeaux's DNA, which matched with the DNA found at the crime scenes. When interrogated, Comeaux confessed.

Case 03 M25 Rapist

Rossmo started working on a case in 1998 involving 27 missing women from Vancouver's downtown Eastside district, a rundown former industrial area. All the missing women were drug addicts and prostitutes. In September 1998, after a group of community workers began demanding an investigation into the matter, the Vancouver Police Department initiated an official search for the missing women. "There were only a few reports of missing persons who had not been found prior to 1995. However, after that the numbers rose significantly," Rossmo recalls. "This is similar to what epidemiologists would call a spatial-temporal cluster; in other words, there were too many events, in too small an area, in too short a period of time, for this just to be random. If these were disease reports, the cluster would indicate an epidemic."

Detective constable Lori Shenher from the missing-persons unit was assigned to the case. Shenher spoke to friends and relatives of the missing women, eventually locating two of them, but also adding 37 more to the list of missing persons. At this point, family and friends of the women asked the police board to offer a reward of $100,000 (£60,000) for information regarding a possible serial killer prowling the Eastside area, a reward equal to what had been offered for a series of residential robberies on the city's affluent west side. The mayor of Vancouver rejected the proposal, claiming that he wasn't financing a "location service for hookers". (After sustained media pressure, a reward was eventually offered.)

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In May 1999, Rossmo presented a report to Fred Biddlecombe, the inspector in charge of the VPD's major-crime section. "He began to come

up with these theories," Rossmo says. "That the prostitutes would be found. That they had overdosed. That their pimps killed them. If you're familiar with Occam's razor, you know how ridiculous these theories were. Why only women? Why only in that location? Why no bodies?" Rossmo's analysis suggested that there was likely a serial killer at work.

In December 2000, the Vancouver Police Department refused to renew Rossmo's contract as a geographic profiler and offered him a reduced rank. Rossmo left.

The Royal Canadian Mounted Police eventually started investigating the case. In February 2002, they searched a 5.6-hectare pig farm in Port Coquitlam, 25 kilometres east of Vancouver. Among the physical evidence recovered were items with DNA from several dead women, buckets with body parts, a .22 revolver and remains of two female bodies in a freezer. They arrested the owner, a millionaire called Robert Pickton, who would later make incriminating statements to an undercover plant in his prison cell, claiming to have killed 49 women, one short of his goal of 50 victims. He was charged with 27 counts of first-degree murder. In 2007, a jury found him guilty of second-degree murder and sentenced him to life imprisonment.

In 2010, a commission of inquiry was set up to investigate the role of the Vancouver Police Department and the Royal Canadian Mounted Police in the Pickton case. Rossmo was called to testify. "What happened was the equivalent of a fire station refusing to send out firetrucks because they only see smoke but no fire," he says now. "All I did was a simple quantitative analysis but Biddlecombe's mind was already made up. I wasn't going to be able to convince him."

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When the final report of the Missing Women Commission of Inquiry was submitted in June 2012, it read: "It is difficult to understand the continued currency of nonsensical theories, such as extended vacations or a sudden rise in deaths due to overdoses without leaving a trace. Senior police officers appeared to consider Det Insp Rossmo's analysis to be 'speculative' despite the fact that it was grounded in solid empirical evidence and factual analysis."

Few agents are fully qualified to deal with serial-killer cases, a training which takes nearly two years. In the UK, there are only three. One was Colin Johnson, who recently retired. He studied under Neil Trainor, who in 1999 was the first British detective to study under Rossmo. Johnson has worked, for instance, in the case of the "M25 rapist" Antoni Imiela who, in the space of a year, attacked at least ten women and girls. The area of the attacks spread over 9,000km<sup>2</sup>. Using Rigel, Johnson generated a geographic profile that identified a 31-kilometre-square area around Woking, Surrey. "Usually the profile identifies an area around the home of the offender, but this was different," Johnson says. "I believed it was his workplace. Most offences occurred on weekdays in working hours.

And we had two offences on one day which indicated he was commuting to the south." The analysis also suggested that the rapist lived in or close to Ashford, where he had committed his first offence, and which, unlike the other attacks, had occurred after dark. "It was likely to be an opportunistic attack which he hadn't planned," says Johnson. "After that, he was aware that the police had his DNA profile so he avoided that area."


Nearly a year into the investigation, the police made a television appeal on Crimewatch. They received more than 10,000 calls, including one from Imiela's neighbour, Kathy Sherwood. "His profile fitted the geography," Johnson says. "We had two key points at a considerable distance apart, one in Woking and another in Ashford. Not too many people have a connection with both." Imiela lived with his wife Christine in the village of Appledore, 16km southwest of Ashford, and he worked for a Woking-based company. On November 21, 2002, the police took Imiela's DNA. It took two weeks for the police to match it with their forensic samples, after which he was swiftly arrested. Two days after the DNA swab, Imiela committed a final crime. He travelled to Birmingham and attacked a ten-year-old, telling her: "I've got nothing to lose."

Rossmo's latest book, Criminal Investigative Failures, analyses the various cognitive biases that affect investigations, such as the Vancouver case. "Once I went to this criminology conference," he recalls. "Some talks given in previous years were either mathematically wrong or suggested tactics that were useless. I have a low tolerance for bullshit."

During his talk, Rossmo showed a slide of a map with scattered dots. "I hope you realise what those dots are," he said to his audience. His next slide showed gruesome crime scenes. "We might be academics," Rossmo says. "But we need to remember what the dots on the map represent.