Research Projects at the Forensic Science Institute
The processes by which human remains are scattered and destroyed by mammalian vertebrate scavenging behaviors are significant to forensic death investigations, in terms of focusing search techniques, improving remains recovery, and contributing to more timely and successful case resolution. This study utilized domestic pig (Sus scrofa) carcasses as human analogues, placed at a wildlife conservation area during three seasons, to assess members of the scavenger guild of the area, their associated behavior, and related effects on remains to address these issues. Carcasses were observed by digital video, motion triggered game cameras, and site visits. Biological radio telemetry transmitters, which are typically used to track living wildlife, were implanted in carcasses to assess long distance movement of skeletal elements. It was shown that there were three main participants in the vertebrate scavenger guild, the coyote (Canis latrans), the Virginia opossum (Didelphis viriginiana), and the bobcat (Lynx rufus). Each of these species left unique taphonomic identifiers on carcasses. They also contributed significantly to the destruction and dispersal of skeletal elements. There were clear patterns in time of carcass acquisition, tissues consumed by each species, and the subsequent dispersal of elements caused by each activity. Mammalian scavenging drastically increased time to skeletonization, which has the potential to lead to inaccurate estimations of post-deposition/post-mortem interval using current techniques. Further research is needed to understand if these patterns are similar in human adult remains and other ecoregions.
Indentification of Human Blood Messenger Ribonucleic Acids Through Non-Polymerase Chain Reaction Based Multiplexing
The identification of human biological fluids has been a significant component of forensic science for hundreds of years, yet the majority of forensically relevant body fluids still cannot be uniquely identified. Due to the increase in the abundance of forensic casework and the lack of confirmatory tests for many body fluids, protein-based methods of body fluid identification are no longer adequate in a world. Over the last ten years, a novel approach for the identification of body fluids utilizing messenger ribonucleic acids (mRNA) has emerged as a promising means of uniquely identifying forensically relevant body fluids. In 2003, Juusola and Ballantyne outlined the potential use of mRNA for the confirmatory identification of numerous forensically relevant human body fluids, and subsequent research demonstrated effective results. The development of a rapid screening method for the conclusive identification of human blood is essential to the advancement of forensic science. Current approaches for such analysis use amplification-based techniques that are not congruent with forensic case workflow. Therefore, an approach that is based on the hybridization of mRNA and DNA and is also independent of amplification would better suit the needs of the forensic community. The majority of the blood specific primers tested amplified the expected target gene. However, the use of generated nucleotide probes cross-linked to a nylon membrane demonstrated minimal success. The administered sample rapidly defused radially, and a substantial amount of background noise existed when imaged. Modification of the protocols continued to produce similar results. Therefore, the hypothesis outline for this thesis is conclusively rejected. While the hybridization of mRNA and DNA was effective, the ability to accurately detect the abundance of these duplexed molecules was inadequate. The significance of this work comes from a greater understanding that an effective method for the detection of mRNA-DNA duplexes is required before a hybridization approach to analysis can be achieved. The need for a more user-friendly mRNA assay for the identification of forensically relevant body fluids remains. While the identification of tissue specific mRNA through hybridization is theoretically possible, a more sensitive detection method must be identified.
Indentification of Morphologically Similar Species of Necrophagous Flies (Diptera: Calliphoridae) in Oklahoma: Reliability and Application of Techniques in a Forensic Setting
The development of taxonomic keys for carrion-associating blow flies (Diptera: Calliphoridae) has greatly enhanced the field of forensic entomology by facilitating identification of species often associated with crime scenes. Keys for morphological identification of blow flies have been developed and refined by Whitworth (2006) and Marshall, et al. (2011). Research involving habitat preferences, ovipositional behavior, developmental rates, and succession to decaying matter has proved vital for the estimation of a post mortem interval (PMI) for crime scene investigators. Within the state of Oklahoma, there is suspected habitat overlap and migration of Calliphoridae species, stemming from varying environmental conditions and resource availability. This study assessed the relationship between morphological and genetic identification of three blowfly species (Lucilia cuprina, Lucilia sericata, and Lucilia mexicana) sampled from eight different locations within Oklahoma and one island location off of the coast of New Hampshire. A 308 basepair amplicon within the cytochrome oxidase I gene of mitochondrial DNA was obtained for twenty-four specimens. An additional genomic location was targeted to support the robustness of laboratory analyses. A 330 basepair amplicon within the 28S large subunit of ribosomal DNA was obtained for thirty-five specimens. Molecular phylogenetic results were compared to morphological identifications in order to ascertain the reliability of the respective laboratory techniques. Morphological and genetic identification techniques confirmed the previously undocumented presence of L. mexicana within Oklahoma. COI data was unreliable for distinguishing between morphologically similar Lucilia species; however 28S phylogenetic assessments were successful in defining most Calliphoridae species. Results serve as a template for future ecological and forensic research.
The purpose of this study is to identify the history and behavioral trends of maternal filicide in the United States. This study examines six cases of filicide that were highly publicized by the media. The media tends to overdramatize certain aspects of cases, which then leads to the overshadowing of actual facts. The data was gathered from court records, police reports, televised offender interviews, and records of psychiatric assessments. The cases that were reviewed were homicides that took place between 1997 and 2005. The study examined the childhood, mental history, prior criminal history, motives and the family-of-origin for each of the filicidal women. The mean age of the mothers at the time they committed the offense was 29.83 years. The women ranged in age from 18 to 38 years. The six women in the study killed a combined total of 17 children (16 males and 1 female). Males were overrepresented as victims in this study compared to other research involving maternal filicide.
Toxicological analysis performed by UPLC/MS provided accurate, precise, and rapid results that indicated the spleen, kidney, and lung all had a consistent postmortem distribution of zolpidem to that of blood. The results of this study confirmed there is a consistent postmortem distribution of zolpidem found in the spleen, kidney, and lung. The study also confirmed it would be possible to roughly estimate, with caution, zolpidem blood concentrations from the spleen, kidney and/or lung. This may help determine if zolpidem was in the therapeutic, toxic, or lethal range when no blood is available.
The Empirical Evaluation and Examination of Breechface Markings on Ten Consecutively Manufactured Pistol Slides
Previously published research and case studies exist pertaining to consecutively manufactured tool marks and the individuality of those markings on tools. This study seeked to assess the Association of Firearm and Tool Mark Examiners (AFTE) Theory of Identification and provide additional research into the investigation of characteristics potentially viewed on the breechfaces of pistol slides. The researcher obtained ten consecutively manufactured Ruger LCP .380 Auto slides for examination. The tool marks exhibited on the breechfaces were macroscopically examined, evaluated in terms of potential for the transfer of subclass characteristics, and examined for the presence of individual characteristics. This research indicated whether breechface markings were accorded to their respective slide or if misidentification by examiners was possible. The importance of this study was in validating the AFTE Theory of Identification through generation of a test for AFTE members. This test required examiners to distinguish between subclass and individual characteristics, identify cartridge cases to their respective slide, and determine whether there was potential for misidentification of breechface markings due to subclass carryover. This study might also function as a test for firearm and tool mark examiners to utilize in their laboratories as a training exercise related to consecutively manufactured breechfaces. The research findings might also facilitate the development of error rates pertaining to this study.
An internal validation study was conducted using the PowerPlex® 16 HS system to ensure proper performance on the Applied Biosystems 3130 Genetic Analyzer in the University of Central Oklahoma laboratory. Manual extraction with the DNA IQTM system was performed. The QuantifilerTM Human Quantification kit was used to quantify the samples. Promega Corporation's PowerPlex® 16 HS system was used to amplify DNA samples on a GeneAmp® PCR System 9700 thermal cycler. Separation occurred through capillary electrophoresis on an Applied Biosystems 3130 Genetic Analyzer. Following parameters established through the validation, an environmental study was conducted to simulate casework samples. The environmental study included ultraviolet treatment, tannic acid, humic acid, and hematin. The results support the multiplexing system is capable of handling DNA samples.
Firearm and tool mark identification relies on criteria that have been accepted in the field to assist firearm examiners in determining if a bullet is fired from a particular firearm. In this research, criteria for firearm conclusions were reviewed, in light of current challenges by the scientific and legal community, concerning the reliability of firearm and tool mark identification theories. The aim of the research is to determine the effectiveness of Consecutive Matching Striae (CMS) criteria with respect to two-dimensional and three-dimensional marks viewed on both known and unknown test bullets of different caliber weapons. This research was conducted using .25 Auto, .380 Auto, .38 SPL, 9mm, .40 S&W, .45 Auto, and 7.62×39mm bullets. All data were used to evaluate the validity of CMS for identification purposes by examining groove impressions. The results revealed that current CMS criteria were valid for firearm identification but some known match comparisons were excluded. Therefore, new proposed criteria were demonstrated for assistance of firearm identification.
Validation of Enzyme-linked Immunosorbent Assays for the Detection of Licit and Illicit Drugs in Human Breast Milk
There are many instances when mothers are unable to provide their own milk, which is the case with many prematurely born infants. Breast milk banks and facilities that process human milk provide an alternative solution to synthetic or animal derived infant formula, allowing babies to receive the benefits of human breast milk. There are many drugs that can pass into a woman's breast milk and cause possible harm to an infant. It is important that donor milk be screened for drugs-of-abuse in order to prevent this from occurring. The purpose of this study was to optimize and validate enzyme-linked immunosorbent assays (ELISA) for the detection of a seven-drug panel in human breast milk. The following Neogen Corporation kits were utilized: Amphetamine Ultra, Benzodiazepine Group, Cocaine/Benzoylecgonine (BZE), Cotinine, Opiate Group, Oxycodone/Oxymorphone, and THC. Sample dilutions that minimized breast milk matrix interference were determined, and cutoff levels for each assay were proposed based on the linear range of the assay. The seven-drug panel was validated through the assessment of drift, precision, and accuracy. The Cocaine/BZE and Opiate Group cutoffs were increased from 30 to 50 ng/mL after several false negative results were obtained during the accuracy portion of the validation. The ELISA assays were validated at two different sites, and the robustness of the method was demonstrated.
Emerging Infectious Disease: Ecological Niche Model and Molecular Identification of Angiostrongylus cantonensis in Rodents from Oklahoma and Louisiana
Emerging infectious diseases (EIDs) have devastating effects on wildlife. Angiostrongylus cantonensis is a zoonotic EID that causes eosinophilic meningitis in humans and neurological illnesses in wildlife. Because A. cantonensis has been documented worldwide and continues to spread, it is a clear example of an EID of potential pathogenicity to both humans and wildlife. The advent of modeling techniques to predict the geographic distribution of pathogens, in conjunction with modern molecular genetics, provides a unique opportunity to gain insight into the distribution of A. cantonensis, and evaluate methods of disease surveillance. I used the modeling program Maxent in combination with IPCC bioclimatic variables to build an ENM to predict current and future distributions of A. cantonensis. I tested these predictions by sampling rodents in SE Oklahoma and Louisiana and analyzing tissues for the parasite using qPCR. Out of 34 samples identified as positive, sequencing analysis revealed only three definitive identifications, one from Sigmodon hispidus and two from Rattus norvegicus. The remaining 31 samples were classified as “false positives” by qPCR. Sequences from positive samples were compared to those on GenBank through BLAST with a match to A. cantonensis. Phylogenetic analysis confirmed relationships by comparing positive sample sequences to A. cantonensis and two closely related species, Angiostrongylus vasorum and Angiostrongylus costaricensis. All phylogenetic methods grouped positive samples and A. cantonensis with 100% confidence. The projected future distribution for A. cantonensis indicates an overall decrease in suitable habitat and range shift. The findings from this study alter our current perspective of A. cantonensis within the United States, and demonstrate the successful application of two important epidemiological techniques that may be applied more broadly to a variety of EIDs.
Investigating the XBOX 360 with Kinect: Implications for Digital Forensics
The Microsoft Xbox 360 with Kinect is the latest online gaming device on the market. The addition of the Kinect gives the Xbox 360 the ability to control games without using a controller, to record voices and to snap digital images of the users. The Xbox 360 is recognized as a popular entertainment and educational device, as well as a platform that can be used by online predators to victimize children or store evidence of criminal activity. Because the Xbox 360 can be used in criminal activity, it is vital that digital forensics examiners be able to recover items of evidentiary value. While some research has been conducted on forensic examination of the Xbox 360, no studies have addressed the evidence left on the Xbox 360 with Kinect. This study examines the evidentiary artifacts left by users on the Xbox 360 with Kinect and the implications for digital forensics examiners.
Evaluation of Familial Search Software for Forensic Investigation using Mutation Rate Adjusted Synthetic Data Sets
The use of a national DNA database, such as CODIS (Combined DNA Index System), to provide leads in unidentified missing persons and violent crime cases can be an advantageous tool for investigators nationwide. When a search of such a database yields no "hit," investigators are not necessarily left with a dead end. Familial searching of DNA databases uses specialized software to examine the database for possible relatives of the individual who contributed to a questioned DNA profile obtained at a crime scene by searching the genetic information of the convicted offenders already in the database. A list of likelihood ratios are ranked and compiled in order to predict the possible biological relationship of the questioned profile and the resulting partial matches from the database. The focus of this research will be concentrated on how known microsatellite mutation rates at the CODIS core loci affect the familial search software's ability to return the correct familial relationships. The researchers will evaluate variables associated with mutation rates in STR, Y-STR (Y-chromosome DNA) and/or mtDNA (mitochondrial DNA) markers in software. To do this, the researchers will be generating synthetic families to test kinship and sibship analysis while manipulating the mutation rates within the software to reflect those, which are now published. Practical considerations such as success rate, false positives rates, false negatives rates, cost of analysis and time will be thoroughly evaluated. Socio-ethical issues will also be explored involving the legality issues of states permitting familial searching with the current software validation capabilities.
The Use of Image Analyzing Software for Muzzle to Target Distance Determination
Muzzle to target distance can be an important aspect in criminal investigations. For most distance determination opinions to be of value to an investigation, the range must be stated such that it gives meaningful information and the resulting bracket of muzzle to target distance must also be defended during courtroom testimony. Current measurement tools lead to subjective opinions by examiners. With objective measurements, examiners can provide improved investigative conclusions that may be defended in court with quantifiable data. Due to the rapid advancement in software technology in recent years, the ability exists to analyze targets with more accurate measurements. Currently, test targets are measured by approximate methods which utilize a high degree of subjectivity. This study examined the application of Image J, image analyzing software, for use in determining muzzle to target distance. This research examined objective data to include particulate density and Gunshot residue dispersion and carried out a statistical replicate study to determine the number of targets needed at a given distance for each gun and ammunition combination.
Comparison of Extraction Kits PrepFiler and DNA IQ for STR Analysis of Contact DNA Samples
Contact DNA evidence is becoming a common occurrence at crime scenes and is often collected and analyzed for human identification. Current Short Tandem Repeats (STRs) techniques are still limited in Low Copy Number (LCN) DNA analysis due to contamination and stochastic effect. Increasing DNA yield from the extraction step is a potential benefit for many investigations. One hundred and fifty samples collected from five female individuals on five commonly-used items were extracted by two forensic extraction systems: DNA IQTM and PrepFiler Kit® with subsequent genotyping by PowerPlex® 16 HS system. Results determined that these extraction systems are not suitable for LCN DNA samples. Only two complete STR profiles were produced without contamination. These findings indicated that further improvements are required in order to utilize STR analysis for LCN DNA.
Use of Digital Forensics Corpora in the Validation of Data Carving Function
The need for an improved validation and verification paradigm in digital forensics is becoming apparent. The current system often results in digital forensics tools being used that have never been tested in reality (Beckett & Slay, 2007). Several articles (Beckett & Slay, 2007; Garfinkel, 2007; Garfinkel, Farrell, Roussev, & Dinolt, 2009) suggest that the use of standardized data sets, or corpora, may be the key to developing a better validation and verification protocol. This paper outlines a study that will utilize digital forensics corpora to validate the carving function of Access Data's Forensic Tool Kit. Does FTK's data carving function perform as intended and recover all possible data? What is the error rate of FTK's data carving function? Does the use of digital forensic corpora provide accurate and reproducible validation results? Is the use of digital forensic corpora a viable validation method for practitioners to use in their own labs? The proposed study will not only evaluate the use of digital forensics corpora in the validation and verification process, but will also serve as a validation study of the FTK's carving function, complete with error rates.
Cyberstalking on Social Networking Websites and its Relationship to Anziety Levels of College Students
In the world that we live in today social networking websites such as Facebook, Myspace, Twitter, Craigslist and many others have become devices for criminals to not only stalk their victims but it has even given them the ability to find them and to easily manipulate them. Cyberstalking is a serious problem and it may continue to get worse with the advances in technology. Cyberstalking has impacts across all age groups and genders and can have a psychological impact on its victims. They may feel stressed and anxious and not be able to trust anyone or be left alone. In this study, university students will be surveyed about their exposure to cyberstalking activities on social networking websites and then will be asked to complete the Beck Anxiety Inventory. Findings will relate to self-reported measures of anxiety and cyberstalking activity.
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.
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.
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.
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.
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.
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.
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.
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.
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-3DTM system. Results address concerns that have been outlined by the National Research Council (2009). Major findings in this study indicate the IBIS BULLETTRAX-3DTM system can assist examiners with better visualization and the ability to provide objective conclusions in bullet comparisons.
The Use of Image Analyzing Software for Muzzle to Target Distance Determination
Muzzle to target distance can be an important aspect in criminal investigations. For most distance determination opinions to be of value to an investigation, the range must be stated such that it gives meaningful information and the resulting bracket of muzzle to target distance must also be defended during courtroom testimony. Current measurement tools lead to subjective opinions by examiners. With objective measurements, examiners can provide improved investigative conclusions that may be defended in court with quantifiable data. Due to the rapid advancement in software technology in recent years, the ability exists to analyze targets with more accurate measurements. Currently, test targets are measured by approximate methods that utilize a high degree of subjectivity. This study examined the application of Image J, image-analyzing software, for use in determining muzzle to target distance. This research examined objective data to include particulate density and Gunshot residue dispersion and carried out a statistical replicate study to determine the number of targets needed at a given distance for each gun and ammunition combination. One pistol, revolver, rifle and shotgun were selected for this study. Test targets were shot five times at distances of: 4, 8, 12, 16, 20, 24 and 28 inches for the pistol, revolver and rifle, and at distances of: 4, 8, 12 and 16 feet for the shotgun. Visual and chemical examinations were performed on test targets using standard protocol procedures, published through the National Institute of Justice (NIJ) Distance Determination Training Module (2011). The targets were digitally photographed through each step and analyzed using the aforementioned protocol and Image J, image-analyzing software. Comparisons were made between the National Institute of Justice model and Image J. Data were obtained and reported using the image analyzing software for particulate count and GSR dispersion.
Identification of Mitochondrial Rodent DNA Isolated from Gnaw Marks on Skeletal Remains
A common problem encountered in forensic casework involving human skeletal remains is the inability to distinguish artifacts left on bones by scavengers from those associated with a victim's death. If an artifact can be conclusively identified as scavenging marks, it will save valuable time and resources that might be spent processing it as possible evidence relating to the death of an individual. This research investigates the possibility of using DNA isolated from rodent buccal cells deposited on skeletal remains as a means of making such a distinction. Any DNA isolated from gnaw marks left on the remains will be amplified and sequenced using the cytochrome b gene in the mitochondrial genome as the target region. This genetic marker shows a high degree of differentiation between different species and allows for more definitive identification of the source of the artifact in question.
Comparative Analysis of Techniques for Shooting Trajectory Reconstruction
The field of shooting trajectory reconstruction is a common practice for law enforcement investigating crime scenes, though little history is actually known about the field. It is proposed that this study will advance crime scene knowledge of the field by applying common geometric principles and modern day crime scene reconstruction techniques. Through comparative analysis, this project will determine beneficial aspects of modern techniques. The study proposes a comparative analysis of two shooting scene reconstruction techniques; specifically, comparing the use of the Smart LevelÔ and calculations utilizing an angle finder to determine the efficiency of each technique. These aspects along with statistical data from crime scene investigators will contribute to the accuracy, precision, and error rate for both tools. This comparison and analysis will provide law enforcement with research enabling them to choose the most effective tool for crime scene analysis and aiding in validating the field of shooting trajectory reconstruction.
The Effects of Commercial Cleaning Agents on Automated DNA Extraction Efficiency and Genetic Profile Quality
As forensic DNA analysis has experienced countless advances in the past several decades, it has gained considerable notoriety among the general public, including those that are involved in the commission of crimes, leading to biological evidence that has been contaminated with various cleaning products in an attempt to conceal or destroy DNA evidence. This research examined the effects that three types of cleaning agents have on the ability of the Applied Biosystems® Automate Express™ Forensic DNA Extraction System to efficiently extract high quality DNA free from inhibiting compounds using the Prepfiler Express™ Forensic DNA Extraction Kit. This study further assessed the impact that these chemicals have on the entire forensic DNA analysis process through evaluation of the quality of genetic profiles using a quantitative scale. A dilution series (neat to 1:1000) was prepared from whole human blood, as well as from a bleach product containing sodium hydroxide, a quaternary ammonium-based multi-surface cleaner, and a carpet cleaner with hydrogen peroxide as the active ingredient. Each blood dilution was combined with each dilution of the three cleaning products and each of those samples was analyzed in triplicate. The amount of DNA extracted from bleach-treated samples was reduced compared to corresponding control samples due to destruction of the DNA prior to extraction. The quantification results from samples treated with both the ammonium-based cleaner and the hydrogen peroxide carpet cleaner were similar to controls. The automated system successfully removed inhibitory compounds from samples containing sodium hydroxide and quaternary ammonium compounds, but the blood samples containing the concentrated hydrogen peroxide cleaner showed increased inhibition. The genetic profile quality scores indicated that the ammonium-based cleaner had no effect on profiles regardless of the dilution ratio of the sample, while samples containing at least equal amounts of bleach and blood can be expected to have complete dropout of all alleles. The inhibition previously mentioned due to the hydrogen peroxide carpet cleaner completely inhibited amplification in samples containing 1:100 or 1:1000 diluted blood treated with neat carpet cleaner. These results indicate that crime scene personnel should document any cleaning agents that may have contaminated biological evidence as it could significantly impact the results of DNA analysis depending on the type of product and its concentration in relation to the evidence.