Criminal dismemberment

: Determining and defining commonly available cutting implements and the analysis of kerf morphology on proxy mediums

  • Grant Thomson

Student thesis: Doctoral ThesisDoctor of Philosophy

Abstract

Homicides involving dismemberment present some of the most challenging investigative processes that law enforcement personnel and forensic practitioners will face. Despite over 180 years of tool mark evidence being presented before courts of law, the assessment of cut marks on bone remains an area of intermittent and limited research.

This study aims to elucidate the status of current ground truth data surrounding cut mark kerf morphology and through the use of innovative research methods determine and define commonly available cutting implements within 4,868 domestic environments. Data from this study indicates that gender is not an influential factor in cutting implement accessibility within domestic settings and identifies that cutting, chopping and sawing implements (suitable for use to facilitate dismemberment of a body) are readily available in both budget and expensive forms within residential locations. This data further enhances research opportunities by providing a reflective taxonomy of cutting implements that are likely to be encountered within criminal dismemberment cases. From this taxonomy, research can now be focussed on specific implements that are known to be obtainable and therefore likely to be encountered.

Eight hundred and forty-three cross sections were generated from micro-CT scans of 319 cuts on porcine femora, dental stone and acrylic polymer using 8 implement types in both budget and expensive formats and 1 implement i.e. machete, in budget only format (n=17). These cross sections were evaluated for morphological profile characteristics over three separate occasions creating a total data set of 2,529 assessments. From these evaluations a novel visual descriptor matrix was designed and developed to aid the accurate classification of cut mark kerf profiles and establish whether characteristics, transferred from cutting implements onto bone and proxy materials, were repeatedly reproduced and categorised repeatedly based on visual perceptual assessments. Using this system, cut mark profile perceptual visual assessments (n=630) produced data that indicates that a variety of shapes are generated in cuts made using the same implements and that these profile shapes challenge established knowledge in the field of cross section class characteristics classification.

From the results of this research, it is suggested that further understanding of cutting implement class characteristics is required for the accurate interpretation of cut marks on bone.
Date of Award2018
LanguageEnglish
Awarding Institution
  • University of Dundee
SupervisorSue Black (Supervisor) & Robert Keatch (Supervisor)

Cite this

Criminal dismemberment: Determining and defining commonly available cutting implements and the analysis of kerf morphology on proxy mediums
Thomson, G. (Author). 2018

Student thesis: Doctoral ThesisDoctor of Philosophy