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Origin of Physical Evidence

Development and analysis of databases for identification of the origin of physical evidence.
(Clark, Horner, Murphy, Schmidt-Rohr, M. Thompson, Houk)

Iowa State University is a land-grant university in the middle of the world's richest farmland. Its history and environment have naturally led it to focus on soil, plant, and animal sciences, and other sciences related to agriculture. Hence, we are in a very strong position to develop and evaluate databases of materials derived from soils, plants, and animals, with the aim of using these databases to identify the origin of soils and biological materials as forensic evidence.

Soil identification is a prime example. At present, soil evidence associated with crimes may be underused because criminalists lack training in standardized soil collection, characterization, and identification techniques. While sophisticated tools and principles have been developed by soil scientists for identification and classification of soil materials, forensic applications would be advanced by the development of standardized, quantitative approaches to characterizing both the clay mineral suite and the organic matter found in soil samples that are often limited in mass. The concomitant development of spectral databases for soils with diverse origins and that vary in management (e.g., industrial vs. agricultural or urban vs. rural) will also strengthen criminalists' abilities to match "unknown" soil samples with similar soils.