Date of Submission

5-2019

Document Type

Thesis

Degree Name

Master of Science in Forensic Science

Department

Forensic Science

Advisor

Brooke Kammrath

Committee Member

Virginia Maxwell

Committee Member

Irina Geiman

LCSH

Envelopes (Stationery), Evidence, Criminal

Abstract

Envelopes can be found at crime scenes when ransom, threat letters or potentially harmful substances are sent to victims. Therefore, they are important probative items of evidence analyzed by forensic document examiners. Manila envelopes are commonly used in the United States to transport or send documents as they are made of thick and durable paper. Although there are many studies on the forensic analysis of office paper and paper-based banknotes, and only a few on white envelopes, there does not exist previously published research on the physical or chemical characterization of manila envelopes. The goal of this research was to analyze manila envelopes using analytical methods normally applied for the analysis of paper with the purpose of characterizing and comparing those sold by different manufacturers as well as the envelopes included in the same and different boxes from the same manufacturer.

Samples from five manila envelopes, size 9x12, from each of the three boxes purchased from ten different brands were examined in order to evaluate whether there are significant differences that can be used for forensic discrimination and/or identification of the manufacturer. The analytical methods were also evaluated to determine the discriminating potential of each when applied to manila envelopes. The analytical methods considered in this research consisted of visual examination to determine physical features, as well as physical measurements of the envelopes and its folds, color examination, the use of Alternate Light Sources (ALS), and chemical analysis using Attenuated Total Reflection Fourier-Transform Infrared (ATR FT-IR) Spectroscopy, Raman Spectroscopy, X-ray Fluorescence (XRF) Spectroscopy, and X-ray Powder Diffraction (XRD). An analytical protocol for the forensic analysis of manila envelopes was developed, beginning with the non-destructive ones, using the most discriminating techniques previously mentioned.

Results indicate that brand discrimination is possible using a combination of the study of physical features and color values. ATR FT-IR spectroscopy Raman spectroscopy, XRF, ALS, as well as physical measurements have value for inclusions and exclusions. There were no differences observed in the XRD data from different envelopes because the diffractograms were dominated by the calcium carbonate peaks, indicating that this method does not have value for discrimination. Finally, differences between boxes within a brand indicate intra-brand variation, which can increase the evidentiary significance of questioned manila envelopes.

It was concluded that detectable chemical and physical differences in the paper of manila envelopes can be used for their characterization and discrimination.

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