National Center for Forensic Science

Fibers

Forensic fiber examination includes both physical match of fabric or cordage based on damaged or cut edges and individual fiber comparisons.  The latter examination consists of determining whether the questioned fiber has the same chemical, microscopic and optical properties as a known sample.  A complete examination will include at least two different techniques to examine each of three characteristics: fiber class, physical characteristics and color.  Instrumentation used includes, but is not limited to: stereomicroscopes, comparison microscopes, and compound microscopes with polarized light capability.   Various chromatographic techniques including gas chromatography and thin layer chromatography may also be used in fiber analysis.

Reference: Scientific Working Group on Materials Analysis, “Introduction to Forensic Fiber Examination”, http://media.wix.com/ugd/4344b0_6d13bd98c3e241b1ac277afbe8e98531.pdf, 2011, accessed March 10, 2016.

NCFS research:

1.NCFS partnered with The West Virginia Forensic Science Initiative (WVU-FSI) to  conduct a census of the transferable fiber population across the United States.  The census categorized the transferable fiber population based on fiber type and color.

2.A statistical comparison of the  visible absorption spectra of the fiber dyes.

3.A molecular-level analysis of the fiber dye  composition performed by direct infusion electrospray ionization – mass  spectrometry (ESI-MS) coupled via an electro spray interface.

For more information contact Dr. Michael Sigman.

4.Development of a fluorescence analytical methodology which is nondestructive and capable of providing highly discriminating  identification of textile fibers.

5.The methodology is also used to investigate the contribution of  intrinsic fluorescence impurities – i.e. impurities imbedded into the fibers  during fabrication of garments – as a reproducible source of fiber comparison.

For more information contact Dr. Andres Campiglia.