Factors affecting the potential for fibre contamination in purpose-designed forensic search rooms

This study investigated fibre movement within and out of a search room, when performing a garment examination. The effect of the collection procedure (taping v. scraping) on the number of contaminant fibres produced, and the effectiveness of a number of cleaning techniques and varying degrees of examiner hygiene were also studied. Fibre movement was found to be dependent upon distance, with fibre populations decreasing with increasing distance from the garment examination area. Most fibres were deposited during the actual examination. Cotton fibres were more easily shed and also found to be airborne for longer periods of time than wool, acrylic and polyester fibres. The 'scraping method' of fibre recovery was found to result in an increase in the number of loose fibres with transfer to the examiner's clothing and a number of fibres exiting the search room. It is unlikely that a completely clean search room can be obtained. However, with proper precautions it is possible to minimise and monitor the contaminant fibre population. These features are presented and discussed in this paper.