Results of a Study to Determine the Probability of Chance Match Occurrences Between Fibers Known to be from Different Sources

Abstract

Abstract The results of a study to determine the frequency of chance match occurrences among fibers known to be from different sources is described. Fibers from articles of clothing of individuals from cases were recovered through an adhesive rolling device and segregated to microscope slides under Cargille H. D. refractive index liquid ND25 = 1.525. They were identified as to type through polarizing microscopy and dispersion staining techniques, and characterized through morphological characteristics and color. The information developed from these steps was entered onto a multi-sort card to permit retrieval of fibers for microscopical comparison by groups. Effectively, 283 882 comparisons involving control and random fibers from 40 articles of fabric were performed. The results reported are believed to give realistic estimates of the probability of chance fiber matches as they can occur in practice. Also given are methods for computing probability, and a discussion of the results.