Forensic Science and Technology Commons^™

Muzzle-To-Target Distance Determination Based On Lead (Pb) Concentration Of Gunshot Residue (Gsr) Using Icp-Oes, Abry Lloyd

Master of Science in Forensic Science Directed Research Projects

The determination of muzzle-to-target distance remains a significant challenge in forensic casework. Current approaches to gunshot residue (GSR) analysis rely primarily on colorimetric testing to indicate chemical components present and subjective interpretation, limiting specificity and contributing to ongoing scrutiny within the field. This study investigates a quantitative method for estimating shooting distance based on the concentration of lead present in GSR samples (w/w%) with the utilization of inductively coupled plasma optical emission spectrometry (ICP-OES). Test firings were conducted using caliber 22 Long Rifle, 9mm Luger, and 40 S&W semiautomatic handguns at defined distances to evaluate the relationship between lead concentration …

Differentiation Of Cell Populations In Saliva-Skin Mixtures Using Autofluorescence Profiling, Kara Fairfax

Master of Science in Forensic Science Directed Research Projects

While DNA profiling of sexual assault evidence can identify biological contributors, determining the tissue source of recovered profiles remains a significant challenge, particularly in cases of suspected oral assault involving mixtures of epithelial cells. The initial goal of this study was to identify non-genetic signatures for differentiating two types of epithelial cells relevant to oral assaults, saliva epithelial cells and epidermal skin cells. To develop tissue-specific signatures, reference cell populations from saliva and epidermal skin surfaces were collected from 20 donors and analyzed using full spectrum flow cytometry.

Results from single-source reference samples showed that saliva-derived particle populations exhibited higher …

Implications Of Substrate Differences In Gunpowder Pattern Analysis: Skin Versus Blotter Paper In Forensic Reconstruction, Faith Duggan

Master of Science in Forensic Science Directed Research Projects

Tattooing, also known as stippling, is a phenomenon that occurs from excess gunpowder being discharged from a firearm into the skin, and presents as reddish-brown or orange lesions surrounding an entrance wound on the skin. Distance determination is a practice used in many forensic laboratories to establish possible ranges of distances between the muzzle of a firearm and a target, and stippling is commonly used for this comparison. Conclusions are made by comparing the unknown pattern to known distance patterns, and determining which one is most similar. In one case, a firearm was discharged at an unknown distance and there …

Advancing Forensic Firearm Analysis: Quantitative Measurement Of Pellet Patterns Using Open Source Software, Inez Staples

Master of Science in Forensic Science Directed Research Projects

Shotgun pellet pattern analysis plays a critical role in forensic firearm investigations, particularly for estimating muzzle-to-target distances. However, conventional methods based on pattern diameter become unreliable when only partial patterns are recovered, as is often the case in forensic scenarios involving soft tissue or incomplete impact surfaces. This study aimed to validate ImageJ, an open-source image analysis software, as a standardized, accurate, and reproducible tool for measuring pellet-to-pellet distances in partial shotgun patterns. The methodology included calibration of ImageJ using a perforated poly board, comparison of manual versus digital measurements on 17 pre-made pellet patterns, and development of a calibration …

Biodistribution And Method Validation Of Xylazine In A Mouse Model Using Liquid-Chromatography-Quadrupole-Time Of Flight Mass Spectrometry, Julia E. Perschbacher

Master of Science in Forensic Science Directed Research Projects

Xylazine is a nonopioid veterinary sedative and an α2 adrenergic receptor agonist. It emerged in the opioid epidemic as an adulterant of illicit fentanyl. As xylazine becomes more involved in fatal overdoses, it is relevant to elucidate its biodistribution post-exposure due to its exacerbation of adverse events, namely respiratory depression, as xylazine’s contributions to existing adverse effects of synthetic opioids is understudied. A bioanalytical method to quantify xylazine and select metabolites in tissue using LC-QToF was validated and applied to a preclinical mouse model in order to characterize xylazine’s biodistribution in whole blood and six tissues at a dose known …

Impact Of Substrates And Deposition Time On Bacteria Associated With Saliva Samples And Its Implication On A Bacterial Signature-Based Body Fluid Identification Method, Olisdey Galano Cruz

Master of Science in Forensic Science Directed Research Projects

Traditional serological methods for body fluid detection are limited by poor specificity and sensitivity, lacking confirmatory capability and thereby increasing the risk of false positives that may compromise the integrity of forensic investigations. While molecular methods such as mRNA, miRNA, and DNA methylation offer improved specificity, they are often hindered by marker instability and operational complexity in routine forensic workflows. Bacterial signature profiling has emerged as a promising alternative, offering enhanced stability, abundance, and compatibility with existing DNA workflows. However, its forensic implementation requires further validation. This study evaluated the effects of substrate type and storage time on the salivary …

Qualitative Method Validation Of Acid/Neutral Drugs Carisoprodol, Meprobamate, And Naproxen Using Liquid Chromatography-Tandem Mass Spectrometry, Kate O. Martin

Master of Science in Forensic Science Directed Research Projects

Meprobamate, carisoprodol, and naproxen are acidic/neutral drugs widely prescribed for muscle relaxation and inflammatory conditions, with frequent detection in forensic toxicology casework due to extensive clinical use. A method to qualitatively evaluate these compounds was developed to unify acid/neutral drug screening. This study incorporated blank blood, antemortem blood, postmortem blood, urine, and liver homogenate as representative biological matrices. Method validation was conducted in accordance with ANSI/ASB Standard 036 for Forensic Toxicology, encompassing key parameters including limit of detection (LOD), endogenous interferences, potential interferences, carryover, processed sample stability, and ionization suppression/enhancement. The validation was performed using the internal standards carisoprodol-D7, meprobamate-D7, …

Novel Time-Since-Deposition Signatures For Canine Blood; Implications For Animal Cruelty Investigations, Alysia M. Townsley

Master of Science in Forensic Science Directed Research Projects

Dogfighting is a felony in all 50 states and is often tied to other organized crime activities including gambling, narcotics, and weapons trafficking. Because of the clandestine nature of dogfighting crimes, it may be necessary to determine the age of blood samples from suspected events, not just the source. In this study, flow cytometry was used to identify cellular autofluorescence signatures for estimating TSD (time-since-deposition) in canine blood deposits up to 6 months old. To accomplish this, blood was taken from canines of various chronological ages and breeds, then deposited to create TSD samples ranging between 1 day and 180 …

Development Of Novel Signatures For Determination Of Cell Types In Blood And Saliva Mixtures, Caitlin Lydon

Master of Science in Forensic Science Directed Research Projects

Determination of tissue source and the time at which a biological material is transferred from its source to another surface, known as the time-since-deposition (TSD), would assist forensic analysts by providing crucial context for DNA profiles generated from biological evidence. Many methods for cell identification have been explored using biomolecule markers such as mRNA, miRNA, and differential DNA methylation. Forensic laboratories have also developed methods for TSD estimation that focus on degradation of biomolecules. Biomolecules such as mRNA or miRNA degrade at different rates due to some being more stable than others. The ratio of stable degrading biomolecules, therefore, can …

Accurate Body Weight Class Prediction From Mirna And Gene Expression In Blood And Saliva Samples, Kimberly Lettner

Master of Science in Forensic Science Directed Research Projects

miRNA interference on protein abundance related to glucose uptake and lipid production has been evaluated in biomedical research and linked to metabolic disorders like severe obesity. The direct regulation of protein abundance caused by miRNAs on a person’s metabolism can lead to an increased weight and overall size. Body size, measured by BMI, provides additional physical descriptions that can be combined with hair color, eye color, age, and skin pigment to aid investigations of unidentified remains or unknown suspects not found in a database. The purpose of this project was to evaluate the miRNA expression of target biomarkers in dried …

Fat And Water Content Effects Of Three Food Substrates (Ground Veal, Ground Beef, And Beef Liver) On Lucilia Sericata (Diptera: Calliphoridae) Development And Mortality, Nicole Dailey

Master of Science in Forensic Science Directed Research Projects

Although temperature has been identified as the most important catalyst affecting blow fly larval development, other variables encountered by these species, such as the fat and moisture content of the food source, may have an impact on accurate estimations of the PMImin in forensic investigations. Thus, body composition differences between human carrion, such as variations in body fat and water percentages between younger and older individuals, or heavier persons, could affect blow fly developmental rates, and in turn cause over or under estimations of the PMImin. In this study, the weight, length, and development times of Lucilia sericata third instar …

The Development And Evaluation Of A Method For Complete Collagenase I Digestion Of Bos Taurus Bone Samples, Reilly Price

Master of Science in Forensic Science Directed Research Projects

Current methods for processing aged forensic bone samples for DNA analysis involve pulverization and organic extraction, which further destroys already degraded DNA and uses large amounts of limited samples. Additionally, the success rates for this type of analysis vary widely as homogenization incorporates PCR inhibitors into the sample. Little research has explored how pulverization results in DNA damage in profiles obtained from skeletal remains. This study proposes an enzymatic digestion method to separate osteocytes from PCR inhibitors in the extracellular bone matrix to improve the quality and quantity of DNA isolated from aged bone samples. The technique described here used …

A Comparative Analysis Of Swabbing Solutions For Sexual Assault Evidence: Direct Impact On Spermatozoa And Dna Recovery, Olivia Q. Kassie

Master of Science in Forensic Science Directed Research Projects

Forensic laboratories struggle with a backlog of sexual assault cases, prompting the need for effective techniques to develop consistent protocols and address scientific gaps. Challenges in recovering optimal DNA from assault evidence stem from factors like collection timing and sampling variables. Variations in lab protocols can lead to differences in DNA yields and profile success. This was observed in a state lab when protocols were developed allowing the use of acetone to swab sexual assault evidence. The use of acetone originated due to their case-routing protocols in multi-section cases involving latent fingerprints. While not necessary for sexual assault and porous …

Evaluation Of Charcoal Strip Extraction Efficiency Under Varying Substrate Conditions, Abby Wester

Master of Science in Forensic Science Directed Research Projects

The ability of a forensic examiner to identify the presence of ignitable liquids (ILs) in fire debris collected from the area of origin of a fire is an essential component for determining intent in fire investigations. However, this relies on an effective extraction method that provides a complete picture of what is present in the debris. In this study, eight substrate materials underwent three different treatments: a low-volume of substrate that was unburned, a low-volume of substrate that was burned, and a high-volume of substrate that was unburned. Each sample was spiked with a 1:1 mixture of gasoline and diesel …

Discrimination Of Blue Denim Fibers Utilizing Physical Characteristics, Optical Properties, Fluorescence Microscopy, Ultraviolet-Visible Microspectrophotometry, And Microchemical Testing, Elkin Howard

Master of Science in Forensic Science Directed Research Projects

Cotton, the most common natural fiber, has numerous uses in the textile industry. This fiber type is ubiquitous in forensic casework due to its prevalence, particularly in blue jeans. The abundance of blue cotton in society and its limited variations in features can diminish the probative value of its presence on items of evidence. While a pair of blue jeans may be constructed with a combination of natural and manufactured fibers, the most likely fiber type to be transferred between sources is cotton. In this study, a comprehensive analytical approach to blue jean fiber analysis was explored to determine if …

Cellular Autofluorescence Signatures For Determining Time Since Deposition Of Whole Blood, Hannah Lamer

Master of Science in Forensic Science Directed Research Projects

Knowledge of the relative window of time that evidentiary biological material was deposited at a crime scene, referred to as the time since deposition (TSD), would help investigators determine which evidentiary items are most probative and assist with scene reconstruction. One commonly encountered body fluid at a crime scene is blood. Various methods for estimating TSD of bloodstains have been developed, but none to date have been validated for use in the forensic laboratory. Recently, flow cytometry measurements of cellular autofluorescence and size/structure have been investigated as a signature for TSD of saliva and touch epidermal cells. This study assessed …

Overcoming The Effects Of Oily Contaminants On Dna Extraction Efficiency Using Dna Iq™ System, Elizabeth G. Gillece

Master of Science in Forensic Science Directed Research Projects

In forensic science DNA extraction and purification are crucial to DNA analysis as evidentiary items vary in DNA quantity and quality. In casework the goal to is maximize DNA yield, remove PCR inhibitors, and develop a full profile while preserving evidence. Extraction methods are developed to target the DNA for optimal isolation. Solid-phase extraction is advantageous as it can extract DNA from a variety of tissue types, it is amenable to automation, and it provides quick and efficient purification of DNA. Solid-phase extraction methods may have complications with contaminants that hinder the quantity and quality of the DNA recovered. In …

A Novel Dual Configuration Dart/Uhplc-Ms/Ms System For The Rapid Analysis Of Psilocybin-Containing Mushrooms And Other Seized-Drug Submissions, Aron R. Jaffe

Master of Science in Forensic Science Directed Research Projects

The use and availability of controlled substances is highly dynamic. When a classical or novel psychoactive substance becomes popular, an influx of seized-drug evidence submissions closely follows, contributing to an ever-growing backlog of exhibits awaiting identification. The need for inclusive, rapid, and robust analytical methods is apparent, as demonstrated by recent growth in hallucinogen use. Psilocybin and psilocin, among other entheogens, have become increasingly popular and an increase of psilocybin mushroom seizures by law enforcement has followed. The structural similarity and thermal lability of many entheogens preclude their identification using many conventional analysis techniques. A DART and UHPLC were interchangeably …

Using The Microbiome To Assess The Health Status Of The Individuals Recovered From The East Marshall Street Well, Arian Karim

Master of Science in Forensic Science Directed Research Projects

In 1994, during the construction of the Kontos Building on the Medical College of Virginia Campus, a well on East Marshall Street was discovered to contain artifacts and human remains of African descent. Upon archaeological analysis by the Smithsonian, the ancestral remains can be dated back to the mid-19th century, when grave robbing and the use of cadavers for anatomical purposes [BS1] in medical schools were common. The human oral microbiome is the second largest human microbiota, containing over 600 species of organisms. Dysbiosis of the oral microbiome can lead to the overgrowth of pathogenic species, resulting in illness and …

Temporal Discrimination Of Lucilia Sericata Pupae Using Dart- Tof-Ms And Statistical Analysis, Nguyen-Khoa N. Pham

Master of Science in Forensic Science Directed Research Projects

Lucilia sericata (Diptera: Calliphoridae) is a forensically important blow fly species. These flies have been extensively studied as they are one of the earliest colonizers of corpses. Adult females blow flies lay approximately 200-2,300 eggs, which upon hatching will feed off the body as they metamorphosize from first to second, and third instars. The third instar larvae then migrate away from the body in a stage known as pre-pupa, and develop into the puparial stage. The adults emerge from the pupa stage, leaving behind their empty puparium. These developmental stages are used by forensic entomologists to determine a minimum postmortem …

Quantitation And Visualization Of Epithelial Cells On Cartridge Cases, Paige Kibler, Christopher Ehrhardt, Katherine M. Philpott, Jody H. West, Stephanie Walcott

Master of Science in Forensic Science Directed Research Projects

Fired cartridge cases are a common type of evidence submitted to forensic DNA profiling but are challenging to analyze because they usually contain only trace amounts of biological material. As such, there is a significant need in caseworking units for new screening techniques to determine if biological material is present and is in high enough quantity to attempt DNA profiling. The goal of this study was to test a new method for quickly visualizing biological material on cartridge cases. Biological deposits were created by handling fired and unfired cartridge cases through a series of conditions. The biological material was collected …

Further Optimization Of A Simplified Protocol For Tooth Sample Preparation For Analysis Using The Applied Biosystems™ Rapidhit™ Id Instrument, Yen H. Dang

Master of Science in Forensic Science Directed Research Projects

Due to the destructive nature of mass casualty incidents (MCIs) or mass fatality events (MFEs), tooth samples are often one of the only viable sources for Disaster Victim Identification (DVI) because of the incredible integrity of the enamel layer surrounding the tooth. However, the resilient structure of the tooth requires harsh chemicals and a labor-intensive sample preparation protocol to ensure successful STR profile development. Considering this difficulty, one of the promising resolutions is the Applied Biosystems RapidHIT™ ID ID platform, which is a fully automated system that is designed to perform cell lysis, DNA isolation, polymerase chain reaction (PCR) amplification, …

The Evaluation Of Semen Extraction Efficiency And Recovery From Reusable Menstrual Underwear, Caitlyn Spencer

Master of Science in Forensic Science Directed Research Projects

A new type of undergarment and feminine product is being submitted to crime laboratories as evidence for sexual assaults: menstrual underwear is underwear that have absorbency and leak-proof abilities and can be washed and re-worn multiple times. The goal of this research was to determine if semen and sufficient DNA could be recovered from reusable menstrual underwear and used to obtain quality DNA profiles. Three menstrual underwear brands of Hanes, Knix, and Thinx were evaluated. Simulated post-coital samples were deposited onto three pairs of each brand of underwear. One pair of each brand was analyzed unwashed, another set was washed …

The Determination Of Ethanol And Phosphatidylethanol (Peth) In Donated Packed Red Blood Cells, Jordan E. Keller

Master of Science in Forensic Science Directed Research Projects

This research investigates the safety and reliability of blood donations by examining the presence of ethanol and phosphatidylethanol (PEth) in packed red blood cells (pRBCs). As blood donation is integral to healthcare, ensuring the safety of blood products is paramount. Current protocols focus on screening for infectious diseases, such as hepatitis C and human immunodeficiency virus (HIV), but do not routinely asses alcohol consumption, which can significantly impact patient outcomes. As a direct indicator of alcohol consumption, ethanol can affect blood quality, interfere with medical treatments, and present legal issues, such as false conclusions or assumptions. Ethanol detection methods include …

Evaluation Of Cytokeratin-Specific Antibody And Autofluorescent Signals As Predictors Of Time Since Deposition For Saliva Samples, Dillon Ryder

Master of Science in Forensic Science Directed Research Projects

In a forensic investigation, STR profiles generated from biological evidence can frequently be informative to identify an individual or provide an investigative lead. However, STR typing does not provide information to answer activity-level questions which can be highly important to a criminal case, such as the Time Since Deposition (TSD) of biological evidence. Determining the relative time in which a biological sample was left at a crime scene would provide additional information regarding the timeline of a crime and a person of interest’s relationship to the scene. One proposed method of estimating TSD is to use flow cytometry to analyze …

Horizontal And Vertical Transmission Of Microbes Associated With Blow Flies Of Forensic Importance, Gabrielle Alisa Burton

Master of Science in Forensic Science Directed Research Projects

Entomological and microbiological evidence can be used in the estimation of postmortem intervals (PMI). This study observes the horizontal and vertical transmission of the microbial community associated with blow flies of forensic importance. Variable region four (V4) of the 16S ribosomal DNA (16S rDNA) was amplified and sequenced from various life stages of blow flies (n=72) using dual-index high throughput sequencing strategy on the MiSeq FGx platform. No significant difference in bacterial community structure was observed between blowfly adults with carrion access and blowfly adults with no carrion access. Dysgonomonas, unclassified Proteobacteria, Escherichia, Ignatzschia, Providencia, …

Bones As An Alternative Matrix For The Detection Of New Synthetic Opioids In Cold Cases: Introducing New Animal Models For Bone:Blood Correlation Studies, Kala N. Babb

Master of Science in Forensic Science Directed Research Projects

Introduction: The growing opioid epidemic in North America presents a call to action to develop new techniques for the identification and quantitation of novel synthetic opioids in uncommon matrices. In instances of extreme decomposition and/or significant scavenging, bone may be the only matrix available. In order to develop an extraction method for synthetic opioids in bone, bone samples were obtained from animal models. The animal model of choice is the rabbit due to their exhibition of spontaneous cortical bone remodeling, a process that is exhibited in humans but not in rats and mice.

Methods: An extraction method was developed to …

Assessment Of The Acidified Hydrogen Peroxide Method On Uncontrolled Fired Cartridge Case Samples, Kylie S. Richardson

Master of Science in Forensic Science Directed Research Projects

The use of fingerprints to identify individuals in forensic cases has been useful for many years due to the persistence and individuality of the prints. In addition, the presence of firearms in forensic casework is steadily increasing over the years. This study aims to expand upon prior research in the development and recovery of latent prints on fired, brass ammunition using an acidified hydrogen peroxide method. Although latent prints are left on the cartridge casing of ammunition during the handling and loading of ammunition into the firearm, it is hypothesized that the pressure within the barrel of the firearm during …

Investigation Into The Relationship Between Dna Content And Dna Yield Prediction And Presence Of A Multiple Contributor Cell Population In Trace Dna, Sarah Holton Roisch

Master of Science in Forensic Science Directed Research Projects

Due to advancements in DNA analysis technology and an increased ability to detect trace quantities of low template DNA, ‘touch’ or trace DNA has become a prevalent form of evidence for forensic investigations. Trace DNA is biological material left on a surface from skin cells after being touched or handled. The success rate of casework could be improved with new methods to non-destructively screen trace DNA to predict DNA yield and whether multiple cell populations are present in the evidence prior to STR analysis. Current methods of trace DNA analysis require quantifying the sample with qPCR followed by STR analysis, …

Optimization Of Microfluidic Device Methodology For Optical Trapping Epithelial Cells In A Mixture, Brittney N. Hackworth

Master of Science in Forensic Science Directed Research Projects

Evidence containing biological mixtures can make DNA interpretation more difficult due to ambiguous allele calls and artifacts that may be present within electropherograms. Separating out these cell mixtures can be advantageous to the analysts’ analysis methods for identifying STR profiles with higher accuracy. A potential cell separation method that could be implemented in the beginning of the forensic DNA workflow is optical trapping.

This research utilized a 5W ytterbium linearly polarized laser split into two optical traps, paired with a microfluidic device to isolate spermatozoa and vaginal epithelial cells from a 1:1 mixture of vaginal fluid and 1:20 diluted seminal …