Forensic Characteristics of Soil

Soil: The Forensic Definition Any disintegrated surface material, natural and/or artificial, that lies on or near the earth’s surface E.g. naturally occurring rocks, minerals, vegetation, animal matter, glass, paint chips, asphalt, brick fragments and cinders

Comparative Analysis Link to geographical location of a crime Soil evidence compared to reference samples collected from crime scene Color (1,100 distinguishable soil colors -2008) Texture

Mineral Naturally occurring crystalline solid

Rock Combination of minerals Types Igneous Metamorphic Sedimentary

Building Materials Brick, Plaster, Concrete Blocks combinations of rocks and minerals Evidence in Breaking & Entering Case

Analysis of Soil Density-gradient Tube A glass tube filled from bottom to top with liquids of successively lighter densities used to determine the density distribution of soil See Text: Criminalistics, p. 113 Fig 4-22

Forensic Value of Soil Typically provides only Class Characteristics

Collection and Preservation of Soil Evidence Establish variation in soil at crime scene by collecting intervals within 100-yd radius Collect samples at alibi locations 1 Tablespoon of top layer is appropriate Individually packaged and labeled Do not remove from an object such as a shoe or garment Do not break up lumps – layering effect may be helpful