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Recovering Latent Fingerprints from Duct Tape after Removal from Various Surfaces using a Dry Ice Acetone Slush

By Vivian Hoang

Abstract

Duct tape is a common item of physical evidence found at many crime scenes. Duct tape has been used to facilitate different crimes, and the criminal population utilizes duct tape in a variety of ways. Some victims of violent crime are restrained or bound with duct tape, and duct tape is used to package items related to criminal activity. While there has been research in the area of preserving and recovering latent fingerprints from duct tape, very few studies have examined the use of dry ice for separation from various surfaces. The purpose of this study was to examine how dry ice reduces the adhesive properties of tape, specifically duct tape, and how the removal affects the quality of recovered latent fingerprints. This study examined the quality of recovered fingerprints separated from various surfaces using a dry ice acetone slush. Initially, a series of preliminary experiments were conducted to observe how specific physical states of dry ice successfully separated tape from wood, metal, and glass. Dry ice was applied in blocks, crushed, powdered, and in an acetone slush. Six brands of duct tape were tested in this study and separated from glass, wood, and metal. Each brand of duct tape was cut into single strips and wrapped multiple times around the surfaces. Two brands of tape were eliminated and a dry ice acetone slush (-78.5°C) provided the most successful method for separation. Various latent print developing methods were used on the adhesive side of duct tape to recover latent fingerprints, such as cyanoacrylate fuming enhanced with Ardrox dye, ninhydrin, 1,8-diaza-9-fluorenone (DFO), Wetwop, and crystal violet. The quality of the recovered latent fingerprints was determined by using a grading system based on ridge detail and minutiae points. Preliminary results have shown that cyanoacrylate fuming followed by Ardrox dye, Wetwop, and crystal violet yielded identifiable fingerprints. Additionally, it was observed that the texture of duct tape could interfere with the quality of developed prints, making the ridge detail difficult to see. The final results of this study could assist latent print examiners by providing an alternative method of removing duct tape and assist in determining which latent fingerprint development method works best after applying the dry ice acetone slush

Publisher: Scholarship & Creative Works @ Digital UNC
Year: 2020
OAI identifier: oai:digscholarship.unco.edu:honors-1035

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