Examination of Firearms Review: 2007 to 2010 - Interpol

4. Textile/ fibre damage
Was-Gubala [19] studied the colour changes in several types of textiles due to
the long-term effects of exposure to laundry detergents. A 14-day study was
carried out using blue, red, and grey/black cotton, wool, acrylic and polyester
textiles. Colour changes were assessed visually by comparing the textile
samples with the untreated (control) material. Fluorescence microscopy (UV
excitation filter) was used to monitor the kinetics of the changes in the colour
of the fibres. The changes observed are assessed from the perspective of
both a fibre analysis expert and the average user/consumer of the products
involved.
Dillinger [20] presented the results of a study to determine the damage
characteristics of dog bites on clothing. This study formed an important part of
the prosecution case in the investigation of a homicide involving a sword.
A presentation by Bennett [21] advocated a more holistic approach to fabric
damage examination and presented a number of case examples in Australia
where they had found this approach to be beneficial.
Canetta et al [22] assessed the application of atomic force microscopy (AFM)
to the examination of nanoscopic morphological changes in the surfaces of
fabrics for the first time. The study material consisted of cotton, woollen, and
viscose textile fibres exposed to burial in different types of soil and immersion
in water (sea and freshwater) for various lengths of time. Examination of the
resulting AFM images allowed the surface texture parameters of the
environmentally stressed fabrics to be measured as a function of the
exposure time. The finest details of the fabric surfaces could also be
visualised, allowing the detrimental effects of the imposed environmental
conditions to be distinguished. This work shows that AFM is potentially a very
useful tool for the forensic examination of textile fibres for distinguishing
between different environmental exposures and forced damage to fibres.
De Wael, and Van Vaerenbergh [23] described a case where the charred
remains of a Molotov cocktail were submitted to the laboratory for
examination. The fibres and textiles laboratory was required to examine the
textile remnants in order to determine the original colour and characteristics of
the material. In this paper they demonstrate how a combination of
microscopy, microspectrophotometry and hot-stage microscopy allowed
examiners to determine the original colour of the fabric and the type of fabric
involved.
Hess [24] reported on a case where it was required to determine whether an
injured party had attempted self immolation or was the victim of an accident.
The various factors affecting the combustion of textiles, including propagation
rates are discussed. These factors, taken into consideration along with testing
of garments and solvents in question, enabled the investigation to conclude
that the injuries were self inflicted.
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