How the dirt on your shoes could prove your guilt
This video from Nature (via Lady Scientists of Tumblr) looks at the work of forensic geologist Lorna Dawson, who has pioneered methods to convict criminals from the dirt on their shoes.
Lorna takes us to a mock crime scene to show how she tests new techniques in soil forensics.
Soil forensics is not new, as Nature notes.
Forensic soil science was nearly 150 years old by the time Dawson took it up. Police in Germany used sandy soil to solve a crime in 1856 and Arthur Conan Doyle noted the forensic potential of dirt three decades later in his first Sherlock Holmes mystery, A Study in Scarlet. In the story, Watson says that Sherlock “tells at a glance different soils from each other. After walks, has shown me splashes upon his trousers and told me by their colour and consistence in what part of London he had received them.”
But the science remained fairly static until recently when a few scientists, such as Dawson, started using sophisticated techniques such as specialised scanning electron microscopy for mineralogy. Dawson plans to add microbial DNA profiling to her armoury.