Vivian Hoang

Document Type

Presentation

Date Created

4-2020

Embargo Date

4-29-2020

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 duct tape, and how the removal affects the quality of recovered latent fingerprints.

The 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 tap 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 tested on the adhesive side of duct tape to recover latent fingerprints, such as cyanoacrylate fuming with Ardrox dye, ninhydrin, 1,8-diaza-9-fluorenone (DFO), Wetwop, and crystal violet. The quality of recovered latent fingerprints will be determined by using a grading system based on ridge detail and minutiae points.

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