Forensic geology solves dirty crimes
Soil forensics are increasingly important in solving crimes, according to a soil scientist from the James Hutton Institute in Scotland speaking today at the British Science Festival in Bradford.
Soil is not just ‘mud’, but a complex mix of organic and inorganic components including minerals, dead organic matter, and very diverse flora and fauna. It is easily transferred onto clothing, footwear, spades and tyres, especially when it is wet. This means that it can provide valuable evidence and intelligence to crime investigators, explained Professor Lorna Dawson, Principal Soil Scientist at the James Hutton Institute in Scotland.
A wide range of techniques is available to link an individual to a crime scene and even to indicate movement through the analysis of different soil layers. Techniques including analysis of the grain size and shape of sand particles, the DNA profiling of soil bacteria, spectral analysis of organic chemicals, and profiles of rare elements and pollen grains can be used to identify locations with varying amounts of spatial accuracy, said Professor Dawson, and new techniques are being developed. Results derived from these methods can be combined probabilistically using Bayesian statistics.
Soil evidence may be used directly in court, or to help to identify geographical areas for investigation. Professor Dawson described a case of aggravated burglary in Derbyshire where CCTV footage showed suspects wearing distinctive footwear. The footwear was linked to the suspects by DNA evidence. It turned out that soil on the soles was from the scene of the crime, while vegetation on the footwear helped to identify the burglars’ entry and exit route.
Professor Dawson is part of the Initiative on Forensic Geology, set up earlier this year by the International Union of Geological Sciences in Paris, to develop forensic geology at an international level.
Andy Wright, British Science Association Media Fellow, Times Higher Education
Soil is not just ‘mud’, but a complex mix of organic and inorganic components including minerals, dead organic matter, and very diverse flora and fauna. It is easily transferred onto clothing, footwear, spades and tyres, especially when it is wet. This means that it can provide valuable evidence and intelligence to crime investigators, explained Professor Lorna Dawson, Principal Soil Scientist at the James Hutton Institute in Scotland.
A wide range of techniques is available to link an individual to a crime scene and even to indicate movement through the analysis of different soil layers. Techniques including analysis of the grain size and shape of sand particles, the DNA profiling of soil bacteria, spectral analysis of organic chemicals, and profiles of rare elements and pollen grains can be used to identify locations with varying amounts of spatial accuracy, said Professor Dawson, and new techniques are being developed. Results derived from these methods can be combined probabilistically using Bayesian statistics.
Soil evidence may be used directly in court, or to help to identify geographical areas for investigation. Professor Dawson described a case of aggravated burglary in Derbyshire where CCTV footage showed suspects wearing distinctive footwear. The footwear was linked to the suspects by DNA evidence. It turned out that soil on the soles was from the scene of the crime, while vegetation on the footwear helped to identify the burglars’ entry and exit route.
Professor Dawson is part of the Initiative on Forensic Geology, set up earlier this year by the International Union of Geological Sciences in Paris, to develop forensic geology at an international level.
Andy Wright, British Science Association Media Fellow, Times Higher Education
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