# Mathematical Digest

### Short Summaries of Articles about Mathematics

in the Popular Press

"The Hound of the Data Points," by Bruce Grierson. *Popular Science,* April 2003.

This long article introduces us to Kim Rossmo and the "geographic profiling"algorithm he developed called *Rigel* that is being used by some policedepartments. Rossmo's work helps direct hunts for criminals, "through thecareful application of that most powerful of investigative tools: a mathematicsequation." This equation, by Canada's "first cop with a Ph.D.", expresses thebasic principles of crime-pattern theory (involving buffer zones and distancedecay) combined with the "least effort" (or cost-benefit analysis) principle.*Rigel* uses all the data related to a crime to generate a geographicalprobability map that enables an optimal strategy to search for suspects. In the"Beltway Sniper" series of shootings, the geographic profiling was noteffective, as the snipers had no anchor point. But in many cases the findingsof *Rigel* were accurate and helpful to the police.

*--- Annette Emerson*