This project looks at the use of micro-CT scanning to assist in the investigation of homicides involving false starts on bone.
Professor Mark Williams
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West Midlands Police.
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In cases of dismemberment, false starts on bone can elucidate details of the tool used. Therefore, collecting as much information as possible from the false start is essential in the evidentiary process.
Traditional toolmark analyses, predominantly microscopy, can be utilised to analyse these marks, however, further detail can be obtained in additional techniques. Micro-CT has the potential to analyse these and can non-destructively obtain 3-dimensional models of false starts. Greater quantitative analysis is possible through analysis of 3D models and can be visually presented to aid both traditional techniques and court cases.
Alongside experimental development, micro-CT is employed to aid in active police casework on homicide cases involving false starts and toolmarks. Assisting toolmark experts and forensic pathologists in injury characterisation and visual presentation at court.
Experimental saw marks are created on cadaveric long bone specimens using a range of commonly available saw types. Micro-CT is then used to produce 3D models of the false starts.
Seven quantitative measurements are taken from the 3D model to assess characteristics of the toolmark and relate these back to the weapon that created it. A regression random forest model is then created to predict the thickness of the saw blade from the false start measurements.
The predictive capability is then tested on a further set of experimental false starts. The statistical model created may then be expanded to allow for a database to predict saw blade thickness from false start measurements.
Qualitative analysis of the dismemberment cases scanned through the Forensic Centre at University of Warwick will also provide academic knowledge to further future experimental studies on false starts.
Interim reports or publications
K. Alsop, W. Baier, D. Norman, B. Burnett and M.A. Williams (2021) Accurate prediction of saw blade thicknesses from false start measurements. Forensic Science International. 318, 110602.