A license to sit

The Platonic bag

The real Numb3rs

We now officially live in the age of the forensic cop show — where police rely not on brass knuckles to bring down perps, but on science. Ever since CSI swept prime time, networks have stumbled over each other to produce ever more procedural dramas where police scientists squint into microscopes and deliver mind-numbing lectures on the how the curl of human hair relates to the ovoid shape of its cross-section. Real-life cops and scientists have a love-hate relationship with these shows, because of two problems: a) The shows create an unrealistic sense of how accurate and easy-to-use these techniques are, and b) juries now expect to be treated to explanations as pat and simple as those in the shows, accompanied, bien sur, by lavish CGI animations.

Anyway, I was intrigued to hear about the premise of CBS’s new procedural thriller (and 1337-speak titled) Numb3rs. According to the New York Times:

Charlie looks at a water sprinkler and has an Archimedes moment: he realizes that the same mathematical principle that allows him to track the path of drops to determine their point of origin could be applied to the distribution of crime scenes on a map. “Are you saying you can tell where the killer is?” Don says slowly and ponderously. His partner drills in the point, saying wonderingly, “If it works we have a whole new system of investigating criminal cases.”

When I read this, a bell in my head went off — because I realized this is “geographic profiling”, a technique invented in 1990 by Vancouver police officer Kim Rossmo (pictured above). In the 80s, criminologists Paul and Patricia Brantingham had proved that serial criminals tend to stick close to home when they commit their crimes. Rossmo took this concept a step further, as a writeup on a criminologist web-site notes …

Rossmo reasoned that if the serial criminal operates close to where he lives, it may be possible to approximate the location of his home by analyzing spatial patterns of the attacks. To test the theory, he wrote a program using proprietary algorithms and statistical analyses of serial crime data collected over several years. The program also incorporated a hunting typology of serial criminals based on the research. When later reviewing George B. Schaller’s authoritative work, The Serengeti Lion, Rossmo found startling similarities in the hunting patterns of African lions and city-dwelling predators.

“Schaller’s typology of how lions hunt matched almost perfectly with the hunting typology of the serial killer. Lions look for an animal that exhibits some indication of weakness — the old, the very young, the infirm, the vulnerable. They will go to a watering hole and hang out because they know it is a draw for their potential targets. We see that all the time with criminal offenders; they go to target-rich environments to do their hunting. Spatial patterns are produced by serial killers as they search and attack. The system analyzes the geography of these, the victim encounter, the attack, the murder and body dumpsites.”

Cool, eh? Which is why I was surprised to find that of the nearly two hundred stories written about the show in the last week, only one actually mentions Rossmo and his work — and that was the New York Post quoting an observation in an online chat room.

blog comments powered by Disqus

Search This Site


I'm Clive Thompson, the author of Smarter Than You Think: How Technology is Changing Our Minds for the Better (Penguin Press). You can order the book now at Amazon, Barnes and Noble, Powells, Indiebound, or through your local bookstore! I'm also a contributing writer for the New York Times Magazine and a columnist for Wired magazine. Email is here or ping me via the antiquated form of AOL IM (pomeranian99).

More of Me


Recent Comments

Collision Detection: A Blog by Clive Thompson