Patterns produced when soil is transferred to bras by placing and dragging actions: The application of digital photography and image processing to support visible observations

•Soil transfer experiments simulate a clothed victim placed or dragged on soil.•Clothed human rescue dummy used in realistic field experiments.•Soil transfer patterns on bras identify different transfer methods and soil types.•Digital photographs analysed to link trace soil patterns on clothing (bras) with soil location.•Image processing identifies trace soil by producing a Munsell soil colour range.

A series of soil transference experiments (STEs) were undertaken to determine whether patterns identified in laboratory experiments could also be recognised at a simulated crime scene in the field. A clothed 55 kg human rescue dummy dressed in a padded bra was either dragged or merely placed on a soil surface at sites with natural and anthropogenic soil types under both wet and dry soil conditions. Transfer patterns produced by dragging compared favourably with those of laboratory experiments. Twelve patterns were identified when a clothed human rescue dummy was dragged across the two soil types in the field. This expanded the original set of eight soil transfer patterns identified from dragging weighted fabric across soil samples in the laboratory.Soil transferred by placing the human rescue dummy resulted in a set of six transfer patterns that were different to those produced by dragging. By comparing trace soil patterns transferred to bras using each transfer method, it was revealed that certain transfer patterns on bras could indicate how the fabric had made contact with a soil surface. A photographic method was developed for crime scene examiners to capture this often subtle soil evidence before a body is transported or the clothing removed.This improved understanding of the dynamics of soil transference to bras and related clothing fabric may assist forensic investigators reconstruct the circumstances of a variety of forensic events.

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