Forensic Science and Technology Commons^™

Validating Machine And Human Decision-Making In Forensic Fire Debris Analysis, Frances A. Whitehead

Graduate Thesis and Dissertation 2023-2024

This work presents a background on the chemical complexity of fire debris analysis, including an ever-present matrix of pyrolysis products as the catalyst that led to the creation of the National Center for Forensic Science's Fire Debris Database. A selection of these 1,000+ casework-relevant ground truth samples was used to create two newly proposed analyst workflows to connect the current method of categorical reporting with evaluative reporting practices reflective of the strength of the evidence. Both workflows use linear sequential unmasking to help mitigate bias, a discrete scoring system for quantification of the analysis, and receiver operating characteristic (ROC) curves …

Chemical Approach To Tire Mark Analysis, John Lucchi

Graduate Thesis and Dissertation 2023-2024

Fatal accidents on the road are an unfortunate daily occurrence, with almost 30,000 deaths resulting from hit-and-runs in the USA between 2006 and 2021. The identification of the driver responsible for this road crime can become a challenge. Nonetheless, the accident scene provides a large amount of trace evidence that can prove critical to this matter, one of them being the tire marks. While traditional tire mark analysis is full of physical information helping the reconstruction of the event, additional information can be extracted from the rubber left during the braking event. Each tire model is manufactured with a specific …

Error Rate Determination Of Latent Print Chemistry Via 1d And 2d Gas Chromatography, Jessica Kindell

Electronic Theses and Dissertations, 2020-2023

Latent print evidence collected from crime scenes are analyzed and compared by examiners using the ACE-V protocol (Analysis, Comparison, Evaluation-Verification) to identify potential suspects. However, smudged and poor-quality prints, usually deemed inconclusive, could be utilized for source association or discrimination based on the chemistry of the oils and sweat that comprises the latent print residue (LPR). For this research, LPRs were collected from various places on the face and analyzed via two-dimensional gas chromatography-mass spectrometry (2D GC-MS), one-dimensional (1D) GC-MS, and direct analysis in real time-high resolution mass spectrometry (DART-HRMS). LPR recovery with two common sample preparation methods, derivatization and …

Complex Dna Mixture Deconvolution By Single Cell Genomics: Direct Physical Cell Subsampling And High Sensitivity Dna Typing, Kaitlin Huffman

Electronic Theses and Dissertations, 2020-2023

Biological evidence is often found at crime scenes and can comprise of DNA from the victim(s) and perpetrator(s) to a crime as well as from individuals with no direct relationship to the incident. This can complicate analysis as DNA mixtures are one of the more difficult sources of biological evidence to interpret. Probabilistic genotyping (PG) has greatly aided in mixture analysis. However, even with PG, standard bulk mixture approaches do not always result in probative results as allele overlap, artifacts, or low-level minor contributors inevitably cause genotype information loss. Therefore, deconvolution of forensic DNA mixtures into their individual component DNA …

Spectrally-Based Color Calibration Of Microscopes For Birefringence Analysis, Olivia Feild

Electronic Theses and Dissertations, 2020-2023

The analysis of colors is omnipresent in forensics. While their use for macroscopic evidence such as soil sees a large amount of research, their correct handling is more challenging when observed under a microscope. Either for hairs or textile fibers, their color (from melanin, dyes or for birefringence analysis) is crucial in being able to compare between fibers found at a crime scene. Typically, color is quantified using a color space, such as RGB, XYZ, L*a*b*, and L*u*v*. Unfortunately, color is very subjective and often difficult to quantify accurately, even using digital detectors. Finding true matches of colors has been …

Reticular Design And Synthesis Of Metal-Organic Frameworks With Targeted Emergent Properties, David Fairchild

Electronic Theses and Dissertations, 2020-2023

The research presented in this dissertation describes the design and synthesis of substitutional-solid-solution-based multivariate metal-organic frameworks (SSS-based MTV MOFs) with functionalized organic linkers to study their emergent properties in the crystalline solid state. The synthetic versatility and tunability of organic chemistry coupled with the predictable organization of inorganic structures enables MTV MOF systems to further the fundamental understanding of structure-composition-property relationships for the targeted design of applied materials due to their ability to control the structure, composition, and property independently. To begin, a set of terphenyl linkers with varied steric and electronic properties were crystallized as a family of UiO-type …

Analysis And Characterization Of Smokeless Powders And Smokeless Powder Residues, Emily Lennert

Electronic Theses and Dissertations, 2020-2023

The ability to associate a smokeless powder, smokeless powder residue, or organic gunshot residue (OGSR) to one another may be helpful in determining the origin of a suspected sample and aid in linking a suspect to a crime scene. In this study, smokeless powders were extracted and analyzed via gas chromatography – mass spectrometry (GC-MS) and direct analysis in real time – high resolution mass spectrometry (DART-HRMS). Subsequently, group definition was performed using hierarchical cluster analysis and principal component analysis followed by internally validated classification models. Then, smokeless powder residues were generated in-lab and extracted. Resulting residue data from each …

Analysis Of Lubricants At Trace Levels Using Infrared Spectroscopy, Tanmai Bandarupalli

Honors Undergraduate Theses

Analysis of trace evidence involved in sexual assault investigations holds considerable potential as a newer avenue of identification when bulk, larger evidence is not found or unreliable. Trace analysis of forensic materials involves common findings such as strands of hair, residues left on clothing, shards of paint or glass, etc. In recent research focused on the analysis of trace materials found as evidence in a sexual assault, there has been promise in condom and bottled lubricant classification based on their chemical profiles that can provide an associative link in an investigation. Few studies have considered the examination of lubricant evidence …

Methodological Improvements In The Mrna Profiling Assays For Incorporation Into Dna Casework Workflows, Paris Volk

Electronic Theses and Dissertations

Currently, DNA profiling is the gold standard to identify an individual. However, determining body fluid origin is important in criminal investigations, offering additional information surrounding the circumstances of a crime. However, crime labs can only definitively identify blood and semen and presumptively saliva using techniques that consume time and sample and do not simultaneously identify all forensically relevant body fluids. This causes many crime labs to want to bypass body fluid identification altogether. Therefore, advances into more definitive molecular-based body fluid methods are necessary. One such technique is mRNA profiling because it provides a highly sensitive and specific approach to …

An Investigation Of Textile Fibers By Means Of Rgb Analysis Of Birefringence, Olivia F. Feild

Honors Undergraduate Theses

Fiber analysis using birefringence has been around for years but has only recently been looked at more closely under a microscope. Recent scientists have proposed methods to correct issues found with fiber analysis using birefringence, yet there has not be a defined perfect method. This research will focus on correcting previously found issues with works by Michel-Lévy and Sorensen's, as well as other scientists involved and perfecting the analysis of fiber through birefringence. The goal will be to take this research one step further into the analysis of textile fibers by RGB value analysis and birefringence. The RGB values will …

Hanging By A Thread: Enhancing The Forensic Value Of Dyed Cotton Trace Evidence Through The Application Of Novel Techniques In Fiber Discrimination, Rachel M. Russo

The Pegasus Review: UCF Undergraduate Research Journal

This thesis examines the capability of current techniques in fiber classification such as UV-visible microspectrophotometry (MSP) (for dye in situ and/or extracted) to discriminate between fibers from sources known to be different. When these methods fail to adequately distinguish the fibers, novel alternative techniques'such as pulsed pumped laser-induced fluorescence spectroscopy (LIF) and liquid chromatography-mass spectrometry (LC-MS)'are utilized to provide definitive forensic evidence.

The FBI Dye Extraction Classification and Chromatography Schemes: Forensic Fiber Examination Guidelines provides the methodology used by the majority of crime labs across the United States (Fong, 1984). In the case of cotton fibers'the most frequently encountered fiber …

Qualitative And Quantitative Elemental Composition Analysis Of The Surrounding Pollen Coating Via Icp-Ms, Brandy Voyer

Electronic Theses and Dissertations

Pollen evidence has proven to be a powerful forensic tool to trace a suspect or item to a victim or a crime scene. This is possible because it is microscopic, abundant in nature, resistant to degradation and decay; it presents dispersal patterns that can be used to generate a 'fingerprint' within specific areas, and has illustrated a unique morphology that can be used to classify species. While the pollen grain morphology has been extensively used to characterize the specific species, not much has been investigated as pertains to the coating that surrounds the pollen grain aside from it being categorized …

Optimizing Laboratory Pyrolysis Methods To Compliment Real World Fire Debris, Richard Coulson

Electronic Theses and Dissertations

Forensic analysts are tasked with determining the presence of ignitable liquid residue in fire debris. Analysis of fire debris allows the analyst to understand how the fire occurred. However, the presence of some substrates can potentially impact the identification of ignitable liquid residue and classification of a sample as positive or negative for the presence of ignitable liquid. Pyrolysis of building materials and furnishings (substrates) lead to background interference within the resulting chromatographic profile. To combat misclassification of a sample as positive for ignitable liquid residue, knowledge of the pyrolysis products from individual substrates is of utmost importance. However, unburned …

Development Of Molecularly Imprinted Polymers For Forensic Applications, Sara Martinez

Electronic Theses and Dissertations

In some forensic disciplines various methods of extraction are used to perform analysis. Among these methods, solid phase extraction (SPE) and solid phase microextraction (SPME) are used in fields such as toxicology and explosives analysis. To enhance extraction efficiency in SPE and SPME, molecularly imprinted polymers (MIPs), which are designer polymers, can be more selective for the binding of an analyte or group of analytes that are similarly structured. Separation of analytes from complex mixtures is possible by utilizing these polymers. This may be especially useful in forensic applications where sample sizes may be small and composition may be complex. …

Mongodb Incidence Response, Cory Morales

Electronic Theses and Dissertations

NoSQL (Not only SQL) databases have been gaining some popularity over the last few years. Such big companies as Expedia, Shutterfly, MetLife, and Forbes use NoSQL databases to manage data on different projects. These databases can contain a variety of information ranging from nonproprietary data to personally identifiable information like social security numbers. Databases run the risk of cyber intrusion at all times. This paper gives a brief explanation of NoSQL and thoroughly explains a method of Incidence Response with MongoDB, a NoSQL database provider. This method involves an automated process with a new self-built software tool that analyzing MongoDB …

Classification Of Silicone-Based Personal And Condom Lubricants Using Dart-Tofms, Lauren Harvey

Electronic Theses and Dissertations

Sexual lubricants are used to enable sexual encounters. There are different types of sexual lubricants such as water-based, oil-based, and silicone-based. They come pre-applied to condoms and separately in bottles as personal lubricants. Although sexual lubricants are intended for consensual use, they are also unfortunately used during the commission of sexual assaults. The analysis of sexual lubricants facilitates sexual assault investigations. With the increased usage of condoms in sexual assault cases, the potential of collected DNA evidence in each case is reduced. In the absence of biological evidence, the presence of sexual lubricants after a sexual assault can provide an …

Characterization Of Post-Fire Priming Cup Residue Using Scanning Electron Microscopy Coupled With Energy Dispersive X-Ray Spectrometry, Molly Terry

Electronic Theses and Dissertations

Ammunition is most often comprised of a lead-based priming mixture which contributes to the traditional characteristics of gunshot residue (GSR). Due to the health risks often associated with lead, lead-free primer alternatives are becoming increasingly more popular. Thus, it is becoming more difficult to determine the presence of GSR based on traditional means, i.e. the presence of lead (Pb), barium (Ba), and antimony (Sb). Eight different ammunitions were purchased which consisted of one lead-based and one lead-free from four different manufacturers, including Winchester, Federal, Liberty, and Sellier & Bellot. Half of the rounds from each manufacturer and chemical composition (i.e. …

The Estimation Of Germ Line De Novo Mutation Rates Of Extended Sets Of Y-Str Haplotypes To Aid In The Differentiation Of Male Biological Relatives In Criminal Investigations, Nicole Masker

Electronic Theses and Dissertations

An important forensic application for Y-chromosome short tandem repeats (Y-STRs) is the identification of male DNA. Since the Y-chromosome is non-recombining and most Y-STRs have slippage mutation rates on the order of 1x10-3 or lower, Y-STR commercial multiplex systems do not yet allow personal individualization. This is problematic in criminal investigations where the persons of interest include males of the same paternal line. In order to obtain discrimination among paternal male relatives, it would be necessary to use a larger number of Y-STRs or a selection of Y-loci with higher slippage mutations with the hope of encountering a germline meiotic …

Quantitative Assessment Of The Effects Of Microbial Degradation Of A Simple Hydrocarbon Mixture, Jessica Kindell

Electronic Theses and Dissertations

Ignitable liquids consist of either a single organic compound or a complex organic mixture. In regards to fire debris analysis, the analyst is responsible for determining if an ignitable liquid residue is present. However, when extracted from soil-containing fire debris evidence, chemical degradation from microorganisms is observed to result in the loss of compounds based on chemical structure. It can also happen when the evidence container is stored at room temperature before analysis. This can present a challenge to the fire debris analyst when identifying and classifying the ignitable liquid residue based on the criteria established by standard test methods. …

Strategies For Enhanced Genetic Analysis Of Trace Dna From Touch Dna Evidence And Household Dust, Katherine Farash

Electronic Theses and Dissertations

In forensic casework it is often necessary to obtain genetic profiles from crime scene samples that contain increasingly smaller amounts of genetic material, called Low Template DNA (LTDNA). Two examples of LTDNA sources are touch DNA evidence and dust bunnies. Touch DNA refers to DNA that is left behind through casual contact of a donor with an object or another person. Touch DNA can be used to prove a suspect was present at a crime scene. Dust bunnies, or dust conglomerates, typically contain trapped shed skin cells of anyone in the vicinity along with fibers, dirt, hair, and other trace …

Providing Context To The Clues: Recovery And Reliability Of Location Data From Android Devices, Connie Bell

Electronic Theses and Dissertations

Mobile device data continues to increase in significance in both civil and criminal investigations. Location data is often of particular interest. To date, research has established that the devices are location aware, incorporate a variety of resources to obtain location information, and cache the information in various ways. However, a review of the existing research suggests varying degrees of reliability of any such recovered location data. In an effort to clarify the issue, this project offers case studies of multiple Android mobile devices utilized in controlled conditions with known settings and applications in documented locations. The study uses data recovered …

The Hermeneutics Of The Hard Drive: Using Narratology, Natural Language Processing, And Knowledge Management To Improve The Effectiveness Of The Digital Forensic Process, Mark Pollitt

Electronic Theses and Dissertations

In order to protect the safety of our citizens and to ensure a civil society, we ask our law enforcement, judiciary and intelligence agencies, under the rule of law, to seek probative information which can be acted upon for the common good. This information may be used in court to prosecute criminals or it can be used to conduct offensive or defensive operations to protect our national security. As the citizens of the world store more and more information in digital form, and as they live an ever-greater portion of their lives online, law enforcement, the judiciary and the Intelligence …

Development Of Micro Volume Dna And Rna Profiling Assays To Identify The Donor And Tissue Source Of Origin Of Trace Forensic Biological Evidence, Brittany Morgan

Electronic Theses and Dissertations

In forensic casework analysis it is necessary to obtain genetic profiles from increasingly smaller amounts of biological material left behind by perpetrators of crime. The ability to obtain profiles from trace biological evidence is demonstrated with so-called ‘touch DNA evidence’ which is perceived to be the result of DNA obtained from shed skin cells transferred from donor to an object or person during physical contact. However, the current method of recovery of trace DNA involves cotton swabs or adhesive tape to sample an area of interest. This "blindswabbing" approach may result in the recovery of biological material from different individuals …

Hfs Plus File System Exposition And Forensics, Scott Ware

Electronic Theses and Dissertations

The Macintosh Hierarchical File System Plus, HFS +, or as it is commonly referred to as the Mac Operating System, OS, Extended, was introduced in 1998 with Mac OS X 8.1. HFS+ is an update to HFS, Mac OS Standard format that offers more efficient use of disk space, implements international friendly file names, future support for named forks, and facilitates booting on non-Mac OS operating systems through different partition schemes. The HFS+ file system is efficient, yet, complex. It makes use of B-trees to implement key data structures for maintaining meta-data about folders, files, and data. The implementation of …

The Implications Of Virtual Environments In Digital Forensic Investigations, Farrah M. Patterson

Electronic Theses and Dissertations

This research paper discusses the role of virtual environments in digital forensic investigations. With virtual environments becoming more prevalent as an analysis tool in digital forensic investigations, it’s becoming more important for digital forensic investigators to understand the limitation and strengths of virtual machines. The study aims to expose limitations within commercial closed source virtual machines and open source virtual machines. The study provides a brief overview of history digital forensic investigations and virtual environments, and concludes with an experiment with four common open and closed source virtual machines; the effects of the virtual machines on the host machine as …

The Application Of Chemometrics To The Detection And Classification Of Ignitable Liquids In Fire Debris Using The Total Ion Spectrum, Jennifer N. Lewis

Electronic Theses and Dissertations

Current methods in ignitable liquid identification and classification from fire debris rely on pattern recognition of ignitable liquids in total ion chromatograms, extracted ion profiles, and target compound comparisons, as described in American Standards for Testing and Materials E1618-10. The total ion spectra method takes advantage of the reproducibility among sample spectra from the same American Society for Testing and Materials class. It is a method that is independent of the chromatographic conditions that affect retention times of target compounds, thus aiding in the use of computer-based library searching techniques. The total ion spectrum was obtained by summing the ion …

The Relative Recoverability Of Dna And Rna Profiles From Forensically Relevant Body Fluid Stains, Charly Parker

Electronic Theses and Dissertations

Biological material (fluids or tissues) whether from the victim or suspect is often collected as forensic evidence, and methods to obtain and analyze the DNA found in that material have been well established. The type of body fluid (i.e. blood, saliva, semen, vaginal secretions, and menstrual blood) from which the DNA originated is also of interest, and messenger RNA typing provides a specific and sensitive means of body fluid identification. In order for mRNA profiling to be utilized in routine forensic casework, RNA of sufficient quantity and quality must be obtained from biological fluid stains and the methods used for …

Determining The Presence Of An Ignitable Liquid Residue In Fire Debris Samples Utilizing Target Factor Analysis, Kelly Mchugh

Electronic Theses and Dissertations

Current fire debris analysis procedure involves using the chromatographic patterns of total ion chromatograms, extracted ion chromatograms, and target compound analysis to identify an ignitable liquid according to the American Society for Testing and Materials (ASTM) E 1618 standard method. Classifying the ignitable liquid is accomplished by a visual comparison of chromatographic data obtained from any extracted ignitable liquid residue in the debris to the chromatograms of ignitable liquids in a database, i.e. by visual pattern recognition. Pattern recognition proves time consuming and introduces potential for human error. One particularly difficult aspect of fire debris analysis is recognizing an ignitable …

Black Writing Ink Analysis By Direct Infusion Electrospray Mass Spectroscopy, Christopher M. Moody

Electronic Theses and Dissertations

An optimized method of extraction, an instrumental analysis method and data analysis was proposed for black writing inks based on direct infusion electrospray-mass spectrometry (ESI-MS). The sampling and analysis method is both minimally destructive and able to assess differences in inks from a reference collection of thirty ballpoint, gel, and rollerball inks. The methanol extracts of ink on paper samples were analyzed with three direct infusion (ESI-MS) methods. Each method varied scan voltage negative and positive, ESI fragmentor applied voltage (+120V, +0V, and -120V), and mobile phase additive. Direct infusion ESI-MS analysis, followed by pair-wise comparisons of the observed ion …

The Forensic Analysis Of Triacetone Triperoxide (Tatp) Precursors And Synthetic By-Products, Kimberly Painter

Electronic Theses and Dissertations

Triacetone Triperoxide (TATP) is a primary high explosive that can be synthesized using commercially available starting materials and has grown in use among terrorists over the past several years. Additives present in the precursors were investigated to see if they carry through the TATP synthesis and can be detected in the final product potentially aiding in the identification of the source. Additives identified in the acetones were also identified in pre-blast and in some post-blast samples. However, these additives are present in trace quantities relative to the TATP, which coupled with the volatility and short lifetimes of some of the …