Forensic Science Institute

Tag: research

Environmental Factors Affecting Latent Print Detail on Porous and Non-Porous Surfaces

The goal of this study was to determine if environmental factors impact the quality of detail in latent prints on non-porous and porous surfaces. Specifically, this study focused on how humidity impacts latent print processing, development, and analysis on tile and paper. Humidity was tested at 30%, 50%, 90% and temperature was maintained between 70 -74 degrees Fahrenheit. Prints were lifted at 1 week time intervals over the course of 3 months. An edited minutiae count generated from AFIS was used to determine what category each print fell under: low quality (0-6 minutiae), moderate quality (7-12 minutiae), or high quality (13 and above minutiae). Multiple statistical tests were performed to determine statistical significance between different variables. Results indicated that prints recovered on white tile with black powder and prints recovered on paper with ninhydrin decrease in quality with increased levels of humidity and also decrease over time at set humidities.

Madison Frese – Summer 2023

Posted on November 20, 2023 by rwilliams73

About Capstone Reflections

The purpose of the Capstone reflection is to identify the “SO WHAT?” So what did you learn during the Capstone? Whom does it affect? How might it be useful? How did your experience connect to your academic work? How did you grow intellectually and/or personally? Since the Capstone was a highly individual experience, the students reflections will also be unique; addressing those specific expectations, problems, skills learned and transformational experiences.

Posted on April 17, 2019 by Dr. Mark McCoy

Research: Method Development and Validation for Drug Identification and Confirmation by LC/MS-MS for Limited-specimen Cases

Driving under the influence of drugs (DUID) cases represent the largest portion of cases handled in most forensic toxicology laboratories. Blood is a commonly used specimen and is often analyzed using gas chromatography-mass spectrometry (GC/MS). A common extraction for this method requires two milliliters of blood. If more than one extraction is necessary, a larger volume of blood is required. Recently, laboratories have started using liquid chromatography-mass spectrometry (LC/MS) to obtain a lower limit of detection and extractions which require less blood to complete. Currently, the Oklahoma State Bureau of Investigation (OSBI) Laboratory operates LC-based extractions which require 250 to 500 microliters of sample to complete, but these are limited to specific drug classes. A general drug screen for forty drugs has been developed and validated using 250 microliters of blood. Even with this reduction of volume requirements, there are still instances in which less than one milliliter of blood is available for use by the analyst. An additional validation has been completed which required 100 microliters of sample to confirm the presence of thirty-nine drugs. A comparison between these methods was completed to verify the sensitivity of the 100 microliter method.

Danielle Ross-Carr – 2017

Posted on April 16, 2019 by Dr. Mark McCoy

Research: Relocation of Remains: Scavenger Patterns in North Central Oklahoma

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.

Kama King – 2015

Posted on April 16, 2019 by Dr. Mark McCoy

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.

Posted on April 16, 2019 by Dr. Mark McCoy

Research: 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.

Posted on April 16, 2019 by Dr. Mark McCoy

Research: Behavioral Characteristics of Maternal Filicide: A Case Study

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.

Posted on April 16, 2019 by Dr. Mark McCoy

Research: Postmortem Distribution of Zolpidem in Aviation Accident Victims

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.

Posted on April 16, 2019 by Dr. Mark McCoy

Research: 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.

Posted on April 16, 2019 by Dr. Mark McCoy

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