Forensic Science Institute

Author: Dr. Mark McCoy – Page 6

Research: Learning Strategies of Digital Forensics Examiners and Students Studying Digital Forensics

Digital Forensics, also known as Computer Forensics, is the investigation of any digital media in order to find evidence. This media can include computer hard drives, flash drives, cell phones, etc… This discipline is relatively new compared to the other forensic disciplines, and is evolving at an exponential rate to keep up with changing technology. Digital forensics investigators often come from different backgrounds. Some have computer science backgrounds and are trained to be investigators while others come from the investigator side and are trained in computer forensics. Some examiners do not have a background in either area, but are being trained in both. There have been many studies concerning the learning strategies of adults. However, no studies have been done to find a common learning strategy among this group. This study determined the predominant learning strategy of a convenience sample of this diverse group to be Problem Solvers using the Assessing The Learning Strategies of AdultS (ATLAS) tool. This allows educators in this field to have a better understanding of how these students learn, and make the process more meaningful. Also, the educators of the on-going training in digital forensics will be more successful in presenting new material to experienced investigators already in the field.

Posted on April 16, 2019 by Dr. Mark McCoy

Research: Analysis of the Composition of Vehicle Tires using Pyrolysis-Gas Chromatography/Mass Spectrometry

Trace and residue evidence is commonly collected at crime scenes and submitted to the laboratory for analysis with the intention of linking a perpetrator to a particular crime. Although a significant amount of time and effort has been put into capturing vehicle tire tread patterns, little research has been published on the characterization of individual tire compositions. Tire manufacturing is a complex process, and the final product is made from of a variety of different ingredients, with rubber being the most abundant constituent (Bodziak, 2008;Williams & Besler, 1995) The three most common rubber components are natural rubber (NR), 1,3-butadiene (BR), and styrene-butadiene (SBR), with most every tire containing a combination of some or all of these materials (Ding & Liu, 1989; Sarkissian, 2007). Microscale sealed vessel pyrolysis-gas chromatography-isotope ratio mass spectrometry (MSSV-Py-GC/IRMS) can be utilized to separate and identify components of tires. The purpose of this project is to determine the variability in polymer composition among brands of tires, different product lines from these brands, and from different locations on a single tire.

Posted on April 16, 2019 by Dr. Mark McCoy

Research: Detection and Identification Techniques for Condom Residues in Sexual Assaults

This study investigated techniques used to detect and identify condom residues in sexual assaults. There were 10 condom brands/sub-brands analyzed, which were chosen based on the geographical locations of the manufacturers. Polarized light microscopy was implemented as an initial means of detecting condom residues by identifying common particulates added during production. It was found that starch was present in only 5 of the condom brands/sub-brands, and no other particulates were identified. These results led to the conclusion that this technique would not be effective as a general screen for the presence of condom residues. Gas chromatography/mass spectrometry (GC/MS), coupled with liquid-liquid extraction and later solid-phase microextraction (SPME) were explored with the intentions of building a database that could suggest a condom brand in the instance of an unknown source. Alkaline extractions were conducted on condom residues and in some instances, derivatization was performed. Analysis revealed that SPME, using a polyacrylate fiber, produced satisfactory results. This technique produced total ion chromatograms with distinct variations between condom brands and some of the sub-brands, while the mass spectra identified multiple components in the residues. Isotope-ratio mass spectrometry (IRMS) was also undertaken to determine if the carbon isotopic ratios of condom residues differed among brands. Three different ratios were observed, suggesting the possibility that manufacturers obtain their lubricants, polydimethylsiloxane, from different geographical sources.

Posted on April 16, 2019 by Dr. Mark McCoy

Research: Church Shooting in the United States

In recent years, Americans have been shocked by the increasing number of mass murders occurring in and around churches in the U.S. Research has formerly examined characteristics of school shooters, workplace shooters, or grouped an excess of varying incidents into the broad category of mass murder, but the behavioral study of church shootings is extremely limited. It is proposed that research be conducted into incident analysis and the common behavioral characteristics of church shooters to determine if a profile can be developed which will aid in understanding and dealing with those who chose to target churches and their members for extreme and indiscriminate violence.

Posted on April 16, 2019 by Dr. Mark McCoy

Research: Maternal Filicide

Incidents of mothers killing their own children are becoming more commonplace in the U.S. In fact the U.S. ranks the highest of any developed nation in maternal filicide. The literature on filicide is inadequate to determine relevant risk factors for maternal filicide. It is proposed that an in-depth analysis of maternal filicide be undertaken to examine the childhood dynamics and common behavioral characteristics of the filicidal mothers, and determine which childhood factors and behaviors may be relevant to risk prediction.

Posted on April 16, 2019 by Dr. Mark McCoy

Research: Linguistic Inquiry and Word Count (LIWC) Analysis to Detect Deception

In law enforcement, a number of techniques and devices have been employed through the years as investigative tools to help identify deception. One technique which is not commonly in use but which is gaining popularity is linguistic analysis of raw text. Linguistic Inquiry and Word Count (LIWC) is a quantitative text analysis software program that categorizes individual words into various dimensions to study individual speech. The premise is that when words are analyzed as decomposed units of speech, a latent meaning of the individual’s thoughts, which are independent of context, are exposed for analysis. It is proposed that research be undertaken to determine whether LIWC analysis could be employed by law enforcement as an investigative tool to indicate deception or possible deception in written statements.

Posted on April 16, 2019 by Dr. Mark McCoy

Service Learning and Forensic Science: The Oklahoma Tornado Victim Project

During the afternoon of May 24, 2011, several large tornados touched down in Oklahoma killing at least ten people and leaving a path of damage fifty miles long. Not only were lives lost, but also computers and other digital devices were severely damaged leaving victims without access to pictures, documents and other vital data stored on these devices. Digital Forensics students, using the knowledge and skills they learned in class and the same high-tech equipment used to solve crimes were able to recover gigabytes of treasured memories and important documents for tornado victims. This service-learning project provided a rich learning experience for students, integrated meaningful community service and strengthen ties with the community.

Posted on April 16, 2019 by Dr. Mark McCoy

Research: Extraction and Quantification of Mitochondrial DNA from Human Hair Extensions

This study seeks to utilize current extraction techniques and detection technologies to recover, quantify, amplify, and sequence mitochondrial DNA (mtDNA) from processed human hair extensions and to determine if the grade or quality of the hair extensions affects the results. In addition to isolating and sequencing mtDNA, this study will seek to differentiate between a processed human hair extension and a real human head hair based on physical, optical, and chemical attributes. For comparative analyses between the processed human hair extensions and real human head hairs both a stereomicroscope and an inverted research microscope will be used to determine if there are any significant physical or optical differences. Chemical analyses will also be conducted to identify the presence of processing chemicals used in the manufacturing of the extensions. Possible instrumentation for chemical evaluation includes solid phase micro-extraction (SPME) or liquid-chromatography mass-spectrometry. The detection of these chemicals may allow for the identification of a human hair as an extension and may also link an extension back to the manufacturer.

Posted on April 16, 2019 by Dr. Mark McCoy

Research: Approaching Objectivity in Firearms Identification: Utilizing IBIS BULLETTRACE-3D’s Sensor Capturing Technology

Firearm examiners are often asked 1) can bullets be matched back to cartridge cases? 2) What bullets leave suitable markings? 3) Does an objective approach for interpreting firearm examiner conclusions exist? The inability to objectively answer questions related to linking evidence and source in firearm and tool mark analysis suggests the need for further studies that offer appropriate, reliable conclusions. The purpose of this study was to provide an objective approach for interpreting Firearm examiner conclusions. A fixed-bin analysis consisting of 53 bins in a side-by-side representation was utilized to analyze regions of interest on a single bullet’s bearing surface acquired in 1.6mm (band) increments by the IBIS BULLETTRAX-3D^TM system. Results address concerns that have been outlined by the National Research Council (2009). Major findings in this study indicate the IBIS BULLETTRAX-3D^TM system can assist examiners with better visualization and the ability to provide objective conclusions in bullet comparisons.

Posted on April 16, 2019 by Dr. Mark McCoy

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