Scientists have made the first steps towards developing a new method to identify criminals' movements using chemical analysis of soil, dust and clothing. This locating system allows security personnel and police to match soil residues on personal items with regional soil samples to determine if the suspect is present at a crime scene. After publication, the work will be presented as a Keynote Lecture at Goldschmidt Geochemistry Conference.Dr Patrice De Caritat is the Principal Research Scientist at Geoscience Australia. Geoscience Australia is Australia's public sector organisation in geoscience."We have done the first trials to determine if geochemical analysis can narrow down a search area. We divided a 260km2 area in North Canberra into squares (1 km x 1km) and took samples of the soil within each cell. The survey area contained 260 km2 and we were given three samples. We were asked to identify the grid cells from which they came. This was a blind experiment. We didn't know where the samples were from until the end. Manhattan Island, at 60 km2, is a comparison. This shows that we were looking at a large area.They were able eliminate 60% of the area under investigation using these methods.Dr. de Caritat stated that "Much of forensics involves elimination." Being able to rule-out 60% of an area is a significant contribution towards successfully locating a sample. The ongoing investigation can be simplified by reducing the investment, risk, and time involved. The system will be more accurate if we have more parameters. Although we have achieved 90% detection in some cases, we believe that this would be too complicated for real-world crime detection.To compare the three blind samples with the previously collected samples, the team used a variety of analytical instruments, including Fourier Transform InfraRed Spectroscopy and X-Ray Fluorescence.Dr de Caritat is also an Adjunct Prof at the University of Canberra's National Centre for Forensic Studies."This proves that our systems are reliable and that we have a new tool to assist in criminal and intelligence investigations. The next stage is the most exciting. Many developed countries have soil databases* that can be used for mineral exploration and land use decision support. To see if our methods can be used to locate samples from these databases, we are plugging them in to the system. This is an alternative to collecting samples for each investigation.In Australia, conventional soil analysis has been used to identify and prosecute criminals. Soil analysis was used to determine the movements of a man accused in a sexual assault against a girl in Adelaide. These are just a few examples. This is where we want to go.In 2017-18 Dr de Caritat was a member of the Australian Federal Police, helping them to develop their ability to analyze soils for forensic locations. He stated:Geoscience Australia has joined the Australian Federal Police, Flinders University, and the University of Canberra to work on a Defence Department project that incorporates environmental DNA (e.g. from local plants) as well as X-Ray Diffraction mineralsogy into soil and dust location systems**.Professor Jennifer McKinley, Queen's University, Belfast, commented that Dr de Caritat's research "is groundbreaking because it integrates robust compositional analysis of multivariate geochemical data to forensic geoscience, and applies this in a novel way to forensic soil originance".###This comment is independent; Prof McKinley wasn't involved in the work.Notes*View examples of soil databases at https:////www. appliedgeochemists. http:// resources/ geochemical-atlases** Please refer to the press release at https:////www. Defenceconnect. com. au/ key-enablers/ 7253-flinders–uni-research–to-help-combatterrorismInformation about publicationCARITAT (P. de), SIMPSON (T. & WOODS(B.), 2019. Predictive soil Provenancing (PSP), an innovative tool for forensic soil provenance analysis. Journal of Forensic Science 64: 1359-1369. DOI: 10.111/1556-4029.14060CARITAT P. de, WOODS B., SIMPSON T., NICHOLS C. HOOGENBOOM L., ILHEO A., ABERLE M.G. 2021. & HOOGEWERFF J. A sequential multivariate approach to soil provenance in urban and suburban settings. Journal of Forensic Sciences online May 2021. DOI: 10.111/1556-4029.
