Application of Raman spectroscopy to forensic fibre cases

Five forensic fibre cases in which Raman spectroscopy proved to be a good complementary method for microspectrophotometry (MSP) are described. Absorption spectra in the visible range are indeed sometimes characteristic of a certain dye but this one can be subsequently identified unambiguously by Raman spectroscopy using a spectral library. In other cases the comparison of Raman spectra of reference fibres and suspect fibres led to an improvement of the discrimination power. The Raman measurements have been performed directly on mounted fibres and the spectra showed only little interference from the mounting resin and glass. Raman spectroscopy is therefore a powerful method that can be applied in routine fibre analysis following optical microscopy and MSP measurements.