How an unsolved murder led to new methods of interpreting forensic soil evidence

Invited Speaker: Dr Kathleen Murray (UTAS)

Dr Kathleen Murray has a PhD in Forensic Soil Science, a Master of Geoscience and a Master of Teaching (Secondary). Her research is published in several international forensic journals. Dr Murray’s interest in forensic science began when she was a Constable in Tasmania Police. She currently holds two academic positions with the University of Tasmania; one as a Research Assistant at the Peter Underwood Centre for Educational Attainment and another with the School of Social Sciences.

Presentation: How an unsolved murder led to new methods of interpreting forensic soil evidence

In a high-profile unsolved murder case from Western Australia, the only forensic evidence was soil evidence on the victim’s clothing and boots. The victim’s husband was put on trial but acquitted for her murder. Because of the lack of published papers that offered a scientific interpretation of trace soil patterns on clothing, the judge could not accept the police interpretation of what had happened to the victim during or after the attack, beyond reasonable doubt.

Not since Locard’s experiments in 1930 has anyone published methods to help police use soil marks/patterns on clothing to interpret what happened to a victim during or after a crime. The aim of this research was to test whether soil patterns on fabric could provide police with a reliable method to interpret trace soil pattern evidence on clothing. Two methods of soil transfer were tested in laboratory and field experiments; namely placing or dragging a simulated clothed human victim across different soil surfaces. Soil evidence was analysed for Munsell soil colour using both a traditional naked eye technique and a new method I developed involving image processing analysis of digital photos of trace soil evidence on clothing.