Inter- and intra- discrimination of cellulose tape using a tape analytical scheme
OA Version
Citation
Abstract
Pressure sensitive tapes are commonly used in crimes; duct tape can be used to bind or as ligatures; electrical tape can be used to hold together firearms and improvised explosive devices (IEDs). Cellulose tape, commonly known as Scotch tape, is not frequently encountered as physical evidence at crime scenes. Determining whether cellulose tape could be discriminated, and therefore probative was the main objective of this research. It was hypothesized that cellulose tapes were too similar to be able to discriminate different brands or styles from one another. To test this hypothesis, 22 readily available cellulose tapes were collected and subjected to a tape analytical scheme. Intra- and inter- roll differences were determined and compared. After completing data collection of the tapes’ widths, thicknesses, physical descriptions, and chemical composition of the backing and adhesive using an Attenuated total reflectance-Fourier transform infrared spectrometer (ATR-FTIR), all but 2 of the 22 tapes could be discriminated. Thickness measurement had a discrimination power (DP) of 57.6%, the lowest DP of all the techniques, and polarized light microscopy had a DP of 99.6%, the highest discriminating ability. Although there was a spread with each analytical step in terms of the ability to discriminate, the total scheme presented should be completed for both the known and unknown tape samples. Further research will continue to increase the distinguishing characteristics used in the examination of cellulose tape, thereby increasing its value as forensic physical evidence.
Description
2024