This final research report addresses 2009 NAS Report concerns, and shows the form, feasibility, and methods to utilize acquired tape edge particles in order to classify adhesive tape rolls and quantitatively associate tape segments with a candidate source.
The author reports on a research project that sought to answer whether the adhesive along the edges of duct tape collects enough variety and amount of very small particles (VSP) post-manufacture to allow comparisons and measurable discrimination among tape segments from different rolls, and to allow meaningful and quantitative associations among tape segments from the same roll. The four specific project objectives were: to develop a practical and effective harvesting protocol for VSP trapped within the adhesive long the edges of duct tape; to harvest VSP from the edges of a population of duct tape specimens, in quantities that are high enough to test their potential to address the 2009 NAS (National Academy of Forensic Science) concerns, and support or refute the association of one piece of tape with another; to apply laboratory methods in the analysis of these VSP and distinguish those particles acquired post-manufacture from particles that were present as manufactured components of duct tape adhesives; and to use previously developed statistical and interpretive methods to measure the discrimination and potential evidential value of VSP acquired post-manufacture along the edges of duct tape. The research project demonstrates one method for addressing the NAS suggestion to exploit characteristics acquired post-manufacture; extends research and development efforts toward quantitative trace evidence associations based on VSP; and serves as a foundation for follow-on research into prototype casework applications for adhesive materials that accumulate VSP post-manufacture. Outcomes include: the development of new methods for harvesting VSP from adhesive materials; the characterization of filler particles in duct tape adhesives; the characterization of particles from duct tape edges; the removal of filler particles from Tape Edge Particle datasets, leaving only acquired tape edge particles (ATEPs); and the classification of duct tapes using acquired VSP.