Indiana University-Purdue University Indianapolis (IUPUI) / Trace evidence is a major field within forensic science. Association of trace evidence samples can be problematic due to sample heterogeneity and a lack of quantitative criteria for comparing spectra or chromatograms. The aim of this study is to evaluate different types of instrumentation for their ability to discriminate among samples of various types of trace evidence. Chemometric analysis, including techniques such as Agglomerative Hierarchical Clustering, Principal Components Analysis, and Discriminant Analysis, was employed to evaluate instrumental data. First, automotive clear coats were analyzed by using microspectrophotometry to collect UV absorption data. In total, 71 samples were analyzed with classification accuracy of 91.61%. An external validation was performed, resulting in a prediction accuracy of 81.11%. Next, fiber dyes were analyzed using UV-Visible microspectrophotometry. While several physical characteristics of cotton fiber can be identified and compared, fiber color is considered to be an excellent source of variation, and thus was examined in this study. Twelve dyes were employed, some being visually indistinguishable. Several different analyses and comparisons were done, including an inter-laboratory comparison and external validations. Lastly, common plastic samples and other polymers were analyzed using pyrolysis-gas chromatography/mass spectrometry, and their pyrolysis products were then analyzed using multivariate statistics. The classification accuracy varied dependent upon the number of classes chosen, but the plastics were grouped based on composition. The polymers were used as an external validation and misclassifications occurred with chlorinated samples all being placed into the category containing PVC.

Trajectory reconstruction of shooting incidents can help investigators determine critical case information regarding the number of shooters involved, their location(s), and intent. The examination of trace amounts of intermediate target materials collected on the surface of spent bullets provides crucial information needed for trajectory reconstruction. Determining the origin of an unknown material adhered to a spent bullet allows for the identification of intermediate targets the bullet either contacted or penetrated during flight. Although significant information can be obtained from examination of these trace materials adhered to spent bullets, this aspect of trajectory reconstruction is often ignored. The ability of different bullet types to collect trace materials from intermediate targets and the ability to associate these trace materials to their origin was examined using microscopy and Direct Analysis in Real Time (DART). Full metal jacket (FMJ), jacketed hollow point (JHP), and lead round nose (LRN) bullets were fired into sheets of five different commonly used building materials (oriented strand board, sanded plywood, white melamine board, synthetic PVC board, and medium density fiberboard) to produce a total of 45 spent bullets to be examined. All spent bullets were examined and photographed using a DSLR camera paired with a stereomicroscope. The spent bullets were then examined using DART/MS to determine if any ion profiles generated from the trace materials could be associated with those of the intermediate target building materials which the bullets were fired through. The collection of trace material from all five types used was highly dependent on the type of bullet. Very minimal amounts of trace materials were observed on the majority of LRN bullets, which failed to produce an identifiable ion signature. The FMJ bullets that were fired through PVC material collected trace material that produced an ion profile, while all other building materials failed to transfer to the FMJ bullets. All JHP bullets collected significant amounts of the five building materials tested inside the hollow point cavity and along the nose of the bullet. In every spent JHP bullet sample, the trace material collected produced a unique ion profile. Additionally, MS data from four of the five building materials tested matched the MS data generated from trace material collected on JHP bullets from the respective target materials.

The awareness of health risks associated with sun exposure, primarily ultra violet (UV) radiation, have played a large role in the introduction of sunless self-tanning products. These products, produced by cosmetic companies, are intended to provide the user with a sun-tanned appearance without exposing the skin to harmful UV radiation. While the manufacturers of these products claim that the products are transfer-free, several reports of the tanner depositing onto the wearers clothing have been documented1. As this is a highly undesirable characteristic for the consumer, the product's ability to transfer onto clothing makes sunless self-tanners a potentially valuable piece of forensic evidence in cases where an altercation between two individuals has occurred, specifically in sexual assaults, beatings, and homicides. The presence of self-tanner on an individual's clothing could help corroborate a story and provide an additional piece of evidence and/or leads to an investigation. The purpose of this study was to determine if sunless self-tanners transfer from skin to clothing. Given that a transfer occurs, this research was also intended to both identify and evaluate the differences seen between self-tanning products using instrumental techniques that would typically be used in forensic labs. Sixteen sunless self-tanning products were added to the skin as directed by the manufacturer. After an assigned time interval since application (15 minutes, 30 minutes, 1 hour, 3 hours, 6 hours, or 12 hours) was reached, a white cotton swatch was used to wipe a portion of the sunless self-tanner off of the skin in attempt to simulate a realistic scenario of an altercation between individuals who may be wearing the product. Observations of the cotton swatches were document. Transferred material on the cotton swatches was analyzed using Fourier Transform Infrared Spectroscopy (FTIR). Analysis of the products prepared directly from the packaging as well as two samples containing transferred material were analyzed using Gas Chromatography- Mass Spectrometry (GC-MS). All of the sixteen samples tested transferred from the skin onto the cotton swatch when forcibly wiped at each time interval. FTIR analysis was unable to discriminate between the commercial products but was able to separate the samples into six groups based on similarities seen between the spectra. Analysis using this instrumental technique was useful in identifying the samples as sunless self-tanning products, but was unable to differentiate further. Analysis of the sunless self-tanners prepared directly from their packaging/bottle using GC-MS was able to differentiate between the products, providing a combination of chemical ingredients that were unique to each product. Analysis of the transferred material on the cotton swatches did not identify all of the chemical components that were earlier considered unique to that sample, however, peaks were observed in the chromatogram that were also present in the samples when prepared directly from their packaging. These transferred samples were able to be identified when a known sample was available for comparison. The instrumental techniques used in this study are useful in analyzing and identifying suspected sunless self-tanner stains on clothing in a crime laboratory setting. The results obtained from this analysis can provide probative information in an investigation.

Elemental analysis in forensic laboratories can be tedious and many trace evidence items are not analyzed to determine their elemental composition. Presently, scanning electron microscopy-energy dispersive x-ray spectroscopy (SEM-EDS) is the primary analytical tool for determining the elemental composition of trace evidence items. However, due to the time it takes to obtain the required vacuum and the limited number of samples that can be analyzed at any one time, SEM-EDS can be impractical for a high volume of evidence items. An alternative instrument that can be used for this type of analysis is laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). While LA-ICP-MS is a very precise and quantitative analytical method that determines elemental composition based on isotopic mass measurements; however, the instrumentation is relatively expensive and therefore is budgetarily prohibitive for many forensic laboratories. It is the purpose of this research to evaluate an inexpensive instrument that can potentially provide rapid elemental analysis for many forensic laboratories. Laser induced breakdown spectroscopy (LIBS) is an analytical method that meets these requirements and offers information about the elemental composition based on ionic, atomic and diatomic molecular emissions.

Condom trace evidence must not be overlooked in sexual assault cases; understanding the chemical and physical characteristics of condoms is imperative if condoms are to be useful evidence. Previous research shows that condom identification is possible, but it is equally important to evaluate durability of condom residues versus time. Using FT-IR, this study examined vaginal swabs from subjects who self-sampled at intervals for up to 72 hours after having intercourse with a condom. This study investigated whether age and the stage of the menstrual cycle affected the durability of residues in the vagina over time. This study revealed that condoms containing nonoxynol-9, silicone-based lubricants, and particulates provide valuable information for identification, and that nonoxynol-9 specifically withstands the vaginal environment for up to 72 hours. Additionally, age and menstrual cycle both appeared to have an effect on the durability of residues although larger sample size is desirable.

Gunshot primer residue (P-GSR) is released from the openings of a firearm when it is discharged12,13. P-GSR is made of microscopic particles that are considered characteristic of being derived from firearm ammunition when composed of barium (Ba), lead (Pb), and antimony (Sb) and have the correct morphology4. Morphology describes the shape of the P-GSR particle, which can be spherical, irregularly shaped, and must be non-crystalline. Forensic labs are commonly requested to test for the presence of P-GSR on evidential items, such as hands, clothing, vehicles, and gloves, in order to provide circumstantial evidence showing that they were, in some way, possibly involved with a shooting. Occasionally these evidential items are also expected to undergo fingerprint processing to potentially link someone to a crime. Latex gloves are often utilized in the commission of a crime with the impression that fingerprints cannot be left behind, however latent prints can often be developed on this non-porous material. Due to the evidential value of fingerprints and in order to ensure that potential prints are not damaged during P-GSR collection, latent print development is routinely performed first. Considering that P-GSR particles are easily dislodged, it is possible that some loss of P-GSR may occur during latent print processing. The purpose of this study was to evaluate the effect of processing a non-porous item for latent fingerprints on the subsequent recovery and detection of P-GSR. Latex gloves were worn during the discharge of either a pistol or a revolver and then processed for latent prints by undergoing cyanoacrylate fuming followed by either white powder or yellow dye. The latex gloves were then sampled for P-GSR using aluminum stubs containing an adhesive coating which were dabbed over the gloves until they loss their tackiness. The stubs were then carbon coated using a Denton Vacuum Desk IV in order to prevent charging in the analytical instrument. Utilizing a JEOL JSM-6460LV Scanning Electron Microscope (JEOL USA Inc., Peabody, MA coupled with an EDAX Apollo X Analyzer (EDAX Inc., Mahwah, NJ) and EDAX Genesis GSR Software, the stubs were processed for three-component particles characteristic of P-GSR. It was determined that P-GSR can still be recovered on latex gloves after undergoing latent print processing involving cyanoacrylate fuming followed by either white powder or yellow dye processing. Three-component particles were found on both the interior and exterior of the latex gloves after being processed for latent prints. On average, 33 P-GSR particles were found on the exterior of the gloves and four P-GSR particles were found on the interior of the gloves. Although significantly less were found on the interior of the gloves (<10), it is recommended that both sides of gloves be stubbed when collecting P-GSR for the greatest chances of collecting three-component particles if they are in fact present on a pair of gloves. Although more particles were found on the gloves that were not processed for latent prints, a sufficient number of particles (≥3 particles) were consistently found on the latex gloves after undergoing latent print processing to provide a positive P-GSR result according to the Massachusetts State Police Crime Lab guidelines for P-GSR analysis. Therefore, this research shows that latex gloves can first be processed for latent prints and then subsequently be processed for P-GSR effectively in order to try and obtain both forms of evidence for a case.

Magistro baigiamajame darbe nagrinėjama ganėtinai svarbi ir aktuali tema „Pėdsakai įvykio vietoje: suradimas, fiksavimas, paėmimas“. Svarbi todėl, kad, turint omenyje dabartinę ne tik Lietuvos, bet ir pasaulio ekonominę situaciją, pastebimai daugėja nusikalstamų veikų, kurios dėl įvairių technologijų ir mokslo vystymosi tampa vis sudėtingesnės ir labiau apgalvotos. Aktuali todėl, kad kiekvienas esame vienodai suinteresuoti, kad kuo daugiau tokių nusikalstamų veikų būtų išaiškinta: surastas nusikaltėlis ir būtų tinkamai už tai nubaustas. Būtent nuo šios vietos ir tampa svarbi šio baigiamojo darbo tema, kuri ir yra skirta supažindinti su pėdsakų samprata, dažniausiai įvykio vietoje randamų pėdsakų rūšimis bei pagrindinėmis taisyklėmis, kaip reikėtų tinkamai pėdsakus užfiksuoti, kad jie neprarastų pagrindinės savo vertybės − tai yra to svarbaus ir neįkainojamo įnašo į sėkmingą tyrimo baigtį. Taigi pirmojoje darbo dalyje trumpai išdėstyta, kas yra pėdsakai, ir argumentuojama, kodėl šiame baigiamajame darbe nagrinėjamos iš esmės dvi pagrindinės pėdsakų rūšys: rankų pėdsakai bei biologiniai pėdsakai. Toliau nagrinėjant šių dviejų pėdsakų rūšių suradimo, paėmimo bei užfiksavimo subtilybes pateikiama nemažai vaizdinės medžiagos. Antroje darbo dalyje pateikta nemažai statistinių duomenų apie užregistruotas nusikalstamas veikas, apie atliktas apžiūras bei kiek buvo paimta pėdsakų ir kokia iš to buvo gauta nauda. Nagrinėjant statistinius duomenis paaiškėja pėdsakų rezultatyvumo... [toliau žr. visą tekstą] / In this master‘s thesis a quite sensitive and topical subject – Trace evidences at the crime scene: locating, fixation and recovery were analized. The criminal situation is getting worse everyday because of economical decline and andvanced technologies that are involved in commiting crime. That is why this topic is so sensitive. All of us are interested in finding and punishing criminal, regardless whether we were affected somehow by the crimes or not. And that is why this subject is so relevant. In this master’s thesis you can find the describtion of the trace evidences’ concept, the kinds of most discovered trace evidences are the main rules how correctly fixate and not to lose traces (this part is the most important to make the whole investigation successful). Why trace evidences were chosen and why only two particular kinds of them (biological and fingerptints) are being analyzed? The first part of the master’s thesis will answer these questions. Also you will find the pictures, which visually depict the beforementioned matter. We can see the statistical information about registered criminal activities, carried out inspections and the amount of taken trace evidences in the second part of master’s thesis. While analyzing this statistical information it’s became obvious why the traces which are being found in the places of the crimes are tend to become less and less informative. In the second part of thesis you can also find the answer how the legal acts of the Republic of... [to full text]

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 design, obtained by a chemical formulation that can become its signature. Supplemental to the molecular profile of the rubber itself, analysis of the trace and contaminant elements can help build the chemical signature for the tire rubber. This work consists of establishing the link between the tire and the skid mark and particles it left during a braking event. The difference between tire models was proved from the elemental analysis of the tire rubber itself, showing that the specific content of minor and trace elements is specific to the model. Expanding to the problem of tire marks, the first challenge consists in efficiently sampling the rubber from the road. The development of an effective procedure to lift the tire particles from the mark is demonstrated in this work. This does present some challenges, including removal of other particles present within the lift and extraction of the tire rubber for further analysis by ICP-MS, providing an elemental profile for the sampled skid mark. Finally, with the skid mark rubber analyzed, it is compared with the elemental profile of the rubber from the source tire. The results of this comparison will be discussed in both simulated (with a lab- made tire mark maker) and field cases (from braking tests performed by the Florida Highway Patrol (FHP)). The results of my research provide the forensic community with the first evaluation of elemental analysis of tire rubber to use this seldom used trace evidence, all along the analytical process, from sampling to analysis to attribution.

Locard’s exchange principle states that every contact leaves a trace. When someone touches a surface or object, they leave a touch deposit. Touch deposits are composed of epithelial cells and random debris from the toucher’s fingers that have been shed onto the contacted surface. This is useful when a fingerprint isn’t distinct enough to be collected; DNA could be recovered instead to create a genetic profile. This project focuses on discovering how cells in each touch deposit are suitable for genetic analysis using micromanipulation techniques and understanding patterns between type of touch and quality of genetic profile. The micromanipulation technique is done using a water-soluble adhesive and a tungsten needle to isolate and collect individual and grouped cells that might be useful for these types of samples. These tools under a microscope allow the skin cells to be separated from the larger sample and individually transferred into tubes for downstream biochemical reactions, including quantification and profiling. While micromanipulation is a technique that has been successful in methods involving epithelial cells, the validity of its use when applied to touch DNA cells, which are in less pristine condition than most samples due to the nature of touch deposits, is still being evaluated. The micromanipulation of grouped cells resulted in more probative genetic profiles and fewer drop-ins, despite inconclusive nucleation, in comparison to individually collected, nucleated cells.

This dissertation consists of five chapters, each of which focuses on various aspects of the forensic discipline of Firearms and Toolmarks. This dissertation for the most part attempts to highlight the exposure of projectiles to blood and the degradation over time of the fine detail, which is necessary for microscopic examination. This study should be of interest to students and qualified role-players in forensic science, the criminal justice system, the law community and the general population globally. Chapter 1 identifies the research problem and the necessary steps that were taken to ensure that the research methodol.ogy applied is relevant and reliable. Chapter 2 focuses on various factors that have to be considered in damage to bullets and investigation procedures that should be followed to ensure that physical evidence is preserved for submitting to a forensic science laboratory. Chapter 3 investigates the degradation effects of fired bullets exposed to various materials in a laboratory environment and the timelines associated with the degradation effects. Chapter 4 evaluates the examination procedures for fired bullets and the contributing factors that may influence the striation marks on bullets needed for microscopic examination. It also examines the scientific method used for firearm identification, and explores the admissibility of physical evidence in a court of law. The final chapter, Chapter 5 discusses the findings and recommendation of this research study. / Criminology / M. Tech. (Forensic Investigation)