FORENSIC SOIL ANALYSIS: CREATION OF A FORENSIC SOIL DATABASE FOR LAW ENFORCEMENT

Locard’s Exchange Principle is based on the theory that every contact leaves a trace. Using this theory, the analysis of mineral compositions in soil can be a powerful forensic tool given the ubiquitous presence of soil and the range of compositions that may be present. A suspect could carry trace amounts of soil away from a crime scene that may be compositionally distinct. These trace soil samples can provide a way of placing suspects at a crime scene when no other evidence exists. Collaboration between the N.C. Geological Survey, N.C. State University Soil Sciences Department and the Southeastern NC Regional Microanalytical and Imaging Center (SENCR-MIC) at Fayetteville State University has resulted in a felony murder conviction based on analysis of mica in soil samples recovered from a suspect.

In the present work, we describe the nature of the analysis used in the case as well as on- going work to evaluate the potential for a forensic [mineral component] soil database. The database is comprised of several soil samples from various counties in southeastern NC and contains modal percentages of all components as well as quantitative chemical analyses of individual phases. The samples were collected by local high school students in an effort to involve them in the research plan and expose them to careers in the sciences (Forensics, Soil Science, Geology and Environmental Science).