The BBC producers of the new documentary about the 1960s Nude Killer have asked me to put them in touch with an investigative expert I know.
Dr Kim Rossmo is a former detective inspector with Vancouver police. It was his most recent work as a geographic profiler that fascinated me. He provided me valuable analysis for The Hunt for the 60s’ Ripper.
The personal geography of criminals can be what condemns them.
We all have our own network of routes and paths – to work, the tube, pub, school. The areas we cover are a giveaway about our habits and routines.
Rigel software helps to expose criminals
Similarly, the movements of serial criminals – burglars, rapists, murderers – can reveal patterns about them and where they may be based. Rossmo uses a sophisticated piece of software he has developed called Rigel to analyse a sequence of crime scenes to guide detectives.
Geographic profiling does not identify a serial criminal or solve a case, but it can be vital in pointing police in the right direction.
The analogy Rossmo uses to explain how geographic profiling works is that of a rotating lawn sprinkler. You can’t predict where the next drop will land, but when enough have fallen the pattern will reveal where the sprinkler is.
We all have comfort zones where we spend most of our time – home to work to home to pub to home. Criminals operate within their comfort zones.
This is a very simplified outline and the success of a geographic analysis lies in the expertise of the profiler. They will spend a lot of time at crime scenes noting factors such as the weather, nearby bus stops, types of housing and businesses.
They will know that robbers tend to travel a greater distance from their home than burglars, that adult criminals travel further than juvenile criminals. Meanwhile, murderers often dispose of their victims further away from home than where they meet them. Continue reading