Did Michelle McNamara help crack the case?

I’ve just finished the fascinating I’ll Be Gone in the Dark by Michelle McNamara.

What an amazing coincidence that California police finally nabbed a suspect for the Golden State Killer crimes so soon after its publication. Finding the perpetrator is the subject of McNamara’s book.

Or was it a coincidence?

Joseph James DeAngelo

It looks as if McNamara’s investigation may have inspired the capture of suspect Joseph James DeAngelo. The cops somehow surreptitiously got his DNA from something he threw away and came up with a match.

What is not clear at the moment is how they latched onto DeAngelo, a former cop. However, the book contains a couple of ideas about he could be caught one day.

It has some geographic profiling of where his murders and rapes, carried out between 1976 and 1986, were committed. He was linked to 50 rapes, 12 murders and many burglaries.

The purpose of this kind of profiling is to indicate where a predator may live or work. The geo-research by a detective McNamara was talking to and by Kim Rossmo, the leading geographic profiler (whom I interviewed for The Hunt for the 60s’ Ripper), both pinpoint the area around Citrus Heights. This is precisely where DeAngelo lived and was arrested last week.

Using DNA to catch DeAngelo

The use of ancestral DNA to unmask the serial killer was another feature of McNamara’s theories for trapping the GSK. McNamara died in 2016 before finishing the book. However, her researcher, Paul Haynes, and journalist Billy Jensen pieced her notes together to finish it.

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BBC documentary talks to geo-profiler Kim Rossmo about Nude Murders

Hammersmith Nude Murders Jack the Stripper Helene Barthelemy

Crime Scene in Brentford where the body of Helene Barthelemy was found on 24 April 1964 © MirrorPix

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 profiler Kim Rossmo

Kim Rossmo

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.

Comfort zones

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