Any viewer of a modern crime drama may think two things. First, that solving a crime takes about 50 minutes, and second, the geniuses in the lab can put any substance into their special analysing machine and tell you exactly what part of the yak the yak hair rope was made from, as well as what the yak had for lunch.
Forensic science is a relatively new field. In the Western World, forensic science made substantial progress around the 1800s when techniques for detecting arsenic and bullet comparisons were developed.
Forensic Soil Science
The field of forensic soil science is even younger. The famous fictional Sherlock Holmes used soil science as clues. In the first book we meet the duo, ‘A Study in Scarlet’, Dr Watson gives an internal appraisal of Holmes. “Geology. – Practical, but limited. 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.”
One of the early known cases of soil science in forensics took place Germany, over 100 years ago.
In 1908, the headless corpse of Margarethe Filbert was found near Rockenhausen in Bavaria. Friendly neighbours suggested Andreas Schlicher as a suspect. A suspected poacher, perhaps this was enough to condemn the man for murder. Ah, the days of the wild accusation.
The District Attorney, however, felt a need for evidence. He was familiar with an 1893 work by Hans Gross titled “Handbuch für Untersuchungsrichter” (Handbook for Examining Magistrates). The book explains the principles of transfer of matter, for example, that dirt on shoes could give clues as to where a suspect or victim had been. So the District Attorney sought the expertise of Georg Popp, a Chemist from Frankfurt.
When questioned, Schlicher denied being near the field where the murder was committed. A search of the area found his trousers, rifle, and ammunition, in a nearby abandoned castle. I can’t find why his trousers were there – perhaps investigators were just as stumped. But by any stretch, waylaid trousers are not enough to accuse someone of murder.
What got Schlicher into a pickle was his shoes. His wife swore she had, as per her wifely duties, cleaned his dress shoes the night before the murder had happened, and he had only worn them that day. The shoes, however, had three different layers of soil adhering to the front of the heel. Popp reasoned that the layers were sequential accumulations.
Popp collected soil samples from around Schlicher’s house, the abandoned castle, and the murder site, and compared them to soil on the shoes. Around Schlicher’s house lay green goose droppings on top of soil with fragments of mica, milky quartz and porphyry. The crime scene soil contained ferruginous clay, red sandstone, and angular quartz. The soil at the castle contained brick dust, coal, and crumbled cement.
On the shoe, the top and oldest layer of dirt on the heel appeared to be goose droppings and other soil comparable to that around Schlicher’s home. The second layer contained fragments of red sandstone like those in the area where the body was found. The final layer contained coal dust, cement and other materials similar to those from a location where Schlicher’s gun and clothes had been found.
The layers present a time sequence. Schlicher had been at his house, then the murder site, then the abandoned castle.
In his testimony, Schlicher said he had only walked in his fields on the day of the crime. However, the fields he referred to contained quartz that was not found on his shoes.
The soil evidence did not prove he committed the murder, rather, it threw his alibi into question.
People lie, soil does not.
This post stems from research for a new popular science book about soil. If you have any topics you think should be researched and written about, shoot me an email or message.