Forensic Soil Science and Geology
CONTAINS OPEN ACCESS
Forensic soil science and geology provides information and operational support to assist the police and law enforcement with criminal and environmental investigations. These include: crime scene examination and the collection of soil and other materials; analysis and interpretation of this geological trace evidence; and searches associated with homicide graves, counter-terrorism and serious and organized crime. This volume provides new and sophisticated field and laboratory methods and operational casework.
The forensic comparison of trace amounts of soil on a pyjama top with hypersulphidic subaqueous soil from a river as evidence in a homicide cold case
Published:October 14, 2021
Robert W. Fitzpatrick, Mark D. Raven, 2021. "The forensic comparison of trace amounts of soil on a pyjama top with hypersulphidic subaqueous soil from a river as evidence in a homicide cold case", Forensic Soil Science and Geology, R. W. Fitzpatrick, L. J. Donnelly
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In a cold case investigation of a 1983 homicide, trace amounts of soil were identified on a 10-year-old victim's pyjama top. Swatch samples were cut from the pyjama top, specifically the hem, to determine the provenance of this questioned soil. A comparative study was undertaken of the questioned soil with control soils from the Onkaparinga estuary using morphological observations with the naked eye and scanning electron microscopy (SEM), chemistry, traditional laboratory X-ray diffraction (XRD) and synchrotron µ-XRD. Synchrotron µ-XRD with high-intensity X-rays provided greater sensitivity and resolution than the laboratory XRD source to identify pyrite and clay minerals on the pyjama top. SEM confirmed that these mineral particles are deeply impregnated in gaps between fibres of the fabric, which are likely to have originated under water with force being applied on the pyjama top – implying that the victim was pushed into the mud. This is substantiated by transference shaking experiments, where mineral particles are dominantly located on the surface of the fabric. The questioned soil samples have a moderately strong degree of comparability with the control hypersulphidic subaqueous soils containing pyrite in the Onkaparinga River estuary – providing evidence that the soils have similar origins. The accused was found guilty by a Supreme Court judge of murder.