Geological Trace Evidence: Forensic and Legal Perspectives

A case study is presented in which exclusionary and comparative analysis of soil from locations associated with a murder and on clothing from the victim and suspect proved important in the investigation of what happened. The soil on clothing comprised 1 to 2 mm diameter ‘specks’ and thus were considered trace evidence: how to handle such quantities of soil is considered in the context of a review of the history of trace evidence in legal cases. The criminal mind is becoming increasingly familiar with clean-up procedures following a criminal event. Police officers and forensic scientists are being faced with scenes of crime that exhibit smaller and smaller amounts of trace evidence available for analysis. Therefore the techniques which are carried out upon recoverable evidence are crucial — as the amount of material available for investigation is diminishing. Investigative research into the analysis of trace mud splashes on different substrate materials attempts to utilise the amount of information which can be obtained at this micro scale. Analysis of these splashes becomes increasingly important when a number of analytical techniques are used to establish their origin: in light of the limited material available non-destructive techniques are therefore top priority in this type of investigative research. This chapter aims to highlight ideas that should be considered during an investigation, information that can be obtained through non-destructive analysis and to provide some guidance as to limitations of analysis techniques.