Analysis for the persistence of single fibers on human fingers and palm by fluorography

Abstract

 Cotton fibers dyed with fluorescein were transferred to human fingers and palms and their persistence were studied by fluorography. Single fibers on the fingers and palms were counted at intervals up to 60 minutes with and without a plastic bag covering the hands. The number of single fibers on uncovered fingers and palms decreased less than 60% of the initial values after 5 minutes when the subject had no contact of their hand to other objects. Contamination by fluorescent fibers from the experimental environment were observed on the uncovered fingers and palms. More than 50% of single fibers on fingers and palms covered with a plastic bag were kept after 60 minutes with no correlation to the attention and behavior of subject. This result can be attributed to transfer of fibers kept in a plastic bag after they had been shed from the hands. The result of this study strongly recommends that the hands of a suspect should be covered with a plastic bag until fibers are examined in order to keep fiber evidence on fingers and palms for a long time and to prevent contamination by foreign fibers.