Identifying the scene of a crime through pollen analysis.

The forensic analysis of pollen involves the comparison of crime scene and reference pollen samples. Successful matches are frequently used to solve time- or location-related crimes. Despite its prospects in criminal investigation, forensic palynology is still underused in casework due to inherent shortcomings such as its limited evidential weighting, scarcity of skilled palynologists dedicated to forensic casework and the laborious nature of analytical procedures. To address these challenges, the current state-of-the-art in forensic palynology is transiting from the traditional light microscopic methods that dominated the early days of palynology to more contemporary approaches like Raman spectroscopy, stable isotope analysis and DNA metabarcoding. The major challenges of these methods, however, include a lack of optimisation to forensic expectations and the unavailability of robust databases to permit accurate data interpretation, and quests to resolve these problems constitute the theme of current research. While reiterating the usefulness of pollen analysis in criminal investigation, this report recommends orthogonal testing as a way of improving the evidential weighting of forensic palynology.

Traces under nails in clinical forensic medicine: not just DNA.

When dealing with complex crimes such as rape and assault, every trace takes on an essential role. The hands are often the only means of defence and offence for the victim as well as a frequent area of contact with the environment; fingernails of a victim are a well-known possible source of DNA of the aggressor; nevertheless, they are more rarely treated as an area of interest for non-genetic material, particularly on living victims. The hyponychium, because of its physiological protective function, lends itself ideally to retaining different kinds of traces representative of an environment or various products and substrates that could shed light on the environment and objects involved in the event. We therefore tested how far this capability of the hyponychium could go by simulating the dynamics of contamination of the nail through scratching on different substrates (brick and mortar, painted wood, ivy leaves, cotton and woollen fabric, soil) and persistence of any contaminant at different time intervals. We have thus shown how these traces may remain in the living for up to 24 h after the event using inexpensive and non-destructive techniques such as the episcopic and optical microscope.

Drone aerial imagery for the simulation of a neonate burial based on the geoforensic search strategy (GSS).

A woman reporting the homicide and burial of an infant in 2004 prompted the creation of an experimental simulated neonate grave shortly before the real search commenced. The real case, documented here, did not use aerial imagery, but used ground-penetrating radar (calibrated to the test site described here) to identify two locations that were probed for gas release and the deployment of victim recovery dogs. We suggest technological advances in remotely sensed aerial imagery that have developed since 2004 will demonstrate their use in focusing such searches by informing a Geoforensic Search Strategy (GSS) and suggesting locations accessible by a perpetrator to identify a burial location using the still-existent analogue site. To test this, in the spring of 2020 a DJI Mavic Pro drone was flown over the control site containing the simulated 2004 burial. Aerial image processing included the creation of orthomosaics, Normalised Difference Vegetation Index (NDVI), Visual Atmospheric Resistance Index (VARI), and photogrammetry. Conventional ground-based geophysical surveys using ground-penetrating radar, guided by this new type of information integrated into the GSS, confirmed that anomalies seen in drone data were the 16-year-old burial. We test this strategy using both the original simulated burial in Northern Ireland and further evaluate it in two recent simulated graves in the United States in more complex scenarios, but with successful results.

Massively parallel sequencing is unlocking the potential of environmental trace evidence.

Massively parallel sequencing (MPS) has revolutionised the field of genomics enabling substantial advances in human DNA profiling. Further, the advent of MPS now allows biological signatures to be obtained from complex DNA mixtures and trace amounts of low biomass samples. Environmental samples serve as ideal forms of contact trace evidence as detection at a scene can establish a link between a suspect, location and victim. Many studies have applied MPS technology to characterise the biodiversity within high biomass environmental samples (such as soil and water) to address questions related to ecology, conservation, climate change and human health. However, translation of these tools to forensic science remains in its infancy, due in part to the merging of traditional forensic ecology practices with unfamiliar DNA technologies and complex datasets. In addition, people and objects also carry low biomass environmental signals which have recently been shown to reflect a specific individual or location. The sensitivity, and reducing cost, of MPS is now unlocking the power of both high and low biomass environmental DNA (eDNA) samples as useful sources of genetic information in forensic science. This paper discusses the potential of eDNA to forensic science by reviewing the most explored applications that are leading the integration of this technology into the field. We introduce novel areas of forensic ecology that could also benefit from these tools with a focus on linking a suspect to a scene or establishing provenance of an unknown sample and discuss the current limitations and validation recommendations to achieve translation of eDNA into casework.

Contribution of plant anatomy to forensic investigation: Tree bark morphology.

Plant science has been more and more utilized in forensic investigation, although its full potential is still to be reached. Plant macroremains are a powerful tool to link a body or other evidence back to a primary crime scene as they can provide detailed information about its previous ecological and geographic location. However, plant macroremains are often poorly preserved and difficult to identify, as diagnostic elements are seldom present within the assemblage occurring on the scene. Plant fragments most likely to be found are those exposed to the environment and resistant to degradation. The bark of woody plants meets these requirements but the possibility of its identification at species level from small fragments is not known. Starting from a real homicide case, where bark splinters were found on the victim, we aimed to assess the forensic potential of bark identification from small fragments like those likely to occur on a crime scene. Two identification keys were prepared for 16 common lowland tree species from Northern Italy; one key used all the available anatomical traits, the second only those from the outer bark. The second key was not able to discriminate some couples of species unambiguously, but could identify the bark fragments of the homicide as Robinia pseudoacacia, as confirmed from direct comparison with a reference sample. Bark fragments deserve to be included into the macroremains to be analyzed during an investigation, but small samples could easily lack diagnostic traits, and the building of a reference collection should be encouraged.

Enhanced analysis of weathered crude oils by gas chromatography-flame ionization detection, gas chromatography-mass spectrometry diagnostic ratios, and multivariate statistics.

Artificially weathered crude oil "spill" samples were matched to unweathered suspect "source" oils through a three-tiered approach as follows: Tier 1 gas chromatography-flame ionization detection (GC/FID), Tier 2 gas chromatography-mass spectrometry (GC/MS) diagnostic ratios, and Tier 3 multivariate statistics. This study served as proof of concept for a promising and new method of crude oil forensics that applies principal component analysis (PCA) and partial least squares discriminant analysis (PLSDA) in tandem with traditional forensic oil fingerprinting tools to confer additional confidence in challenging oil spill cases. In this study, weathering resulted in physical and chemical changes to the spilled oils, thereby decreasing the reliability of GC/FID and GC/MS diagnostic ratios in source attribution. The shortcomings of these traditional methods were overcome by applying multivariate statistical tools that enabled accurate characterization of the crude oil spill samples in an efficient and defensible manner.

Soil chemical markers distinguishing human and pig decomposition islands: a preliminary study.

The decomposition of vertebrate cadavers on the soil surface produces nutrient-rich fluids that enter the soil profile, leaving clear evidence of the presence of a cadaver decomposition island. Few studies, however, have described soil physicochemistry under human cadavers, or compared the soil between human and non-human animal models. In this study, we sampled soil to 5 cm depth at distances of 0 cm and 30 cm from cadavers, as well as from control sites 90 cm distant, from five human and three pig cadavers at the Australian Facility for Taphonomic Experimental Research (AFTER). We found that soil moisture, electrical conductivity, nitrate, ammonium, and total phosphorus were higher in soil directly under cadavers (0 cm), with very limited lateral spread beyond 30 cm. These patterns lasted up to 700 days, indicating that key soil nutrients might be useful markers of the location of the decomposition island for up to 2 years. Soil phosphorus was always higher under pigs than humans, suggesting a possible difference in the decomposition and soil processes under these two cadaver types. Our preliminary study highlights the need for further experimental and replicated research to quantify variability in soil properties, and to identify when non-human animals are suitable analogues.

Civilian Forensic Technician and Sworn Police Officer Job-Related Stress.

Forensic Technicians provide crime scene investigation services and are exposed to stressful violent crimes, motor vehicle accidents, biological or chemical hazards, and other appalling imagery. Forensic Technicians would likely experience physical and psychological stress after exposure to trauma, and security vulnerabilities similar to Sworn Police Officers. The perceived availability of mental health resources, job-related physical, psychological stress, and traumatic experiences of both Forensic Technicians and Sworn Police Officers from California law enforcement agencies were investigated using a self-reported survey. Responses were evaluated for any significant differences in the perceived stress, job-related physical stress, and resulting psychological impact affecting the participants. The survey contained a mix of True/False, Circle/Check the Appropriate Box, or Likert Scale (1-5) responses. The results were evaluated statistically and discussed. Results indicated Sworn Police Officers and Forensic Technicians have different on-duty stress levels, but similar off-duty stress levels. Nearly two-thirds of 54 job-related stressors were not significantly different between the two occupations. However, Forensic Technicians reported more adverse effects in 17 physical and psychological job-related activities compared with Sworn Police Officers. Forensic Technicians reported lower awareness levels and availability of agency mental health support services than were reported by Sworn Police Officers. This study reports for the first time an unexpected outcome that perceived and job-related psychological stress is greater for Forensic Technicians than Sworn Police Officers. Possible reasons for this disparity will be discussed as well as stress management tools that should be implemented to reduce health risk factors for both career professionals as well as increase public safety.

Research Progress on Forensic Palynology and Its Application in Forensic Science.

ABSTRACT: Forensic palynology is to apply palynology to the field of forensic science, using pollen and spores to solve issues in juridical practice, such as civil and criminal issues. Sporopollens have a small size, wide distribution, diverse morphology, can be easily transferred, have durability, and is not easily noticed. It can provide strong investigation and related evidence for case detection as good trace evidence. The application of palynology in forensic science has achieved certain success, but it is underutilized in most countries. This paper analyzes the evidence value provided by sporopollen, collection of the sporopollen samples, the progress in detection technology and challenges ahead, based on the biological characteristics of sporopollen, combined with recent successful cases in forensic science, to comprehensively discuss the research progress in forensic palynology and its application prospects in forensic science.

Using museum pelt collections to generate pollen prints from high-risk regions: A new palynological forensic strategy for geolocation.

The use of pollen as a forensic tool for geolocation is a well-established practice worldwide in cases ranging from the provenance of drugs and other illicit materials to tracking the travel of individuals in criminal investigations. Here we propose a novel approach to generation of pollen databases that uses pollen vacuumed from mammal pelts collected historically from international areas that are now deemed too high risk to visit. We present the results of a study we conducted using mammal pelts collected from Mexico. This new investigative technique is important because, although it would seem that the ubiquitous and geo-specific nature of pollen would make pollen analysis among the most promising forensic tools for law enforcement and intelligence agencies, it is not the case. The process is notoriously slow because pollen identification is a tedious task requiring trained specialists (palynologists) who are few in number worldwide, and the reference materials necessary for geolocation usually are rare or absent, especially from regions of the world that are no longer safe to visit because of war or threat of terrorism. Current forensic palynological work is carried out by a few highly trained palynologists who require accurate databases of pollen distribution, especially from sensitive areas, to do their jobs accurately and efficiently. Our project shows the suitability of using the untapped museum pelt resources to support homeland security programs. This first palynological study using museum pelts yielded 133 different pollen and spore types, including 8 moss or fern families, 12 gymnosperm genera and 112 angiosperm species. We show that the palynological print from each region is statistically different with some important clustering, demonstrating the potential to use this technique for geolocation.

The evolution of the field of legal medicine: A holistic investigation of global outputs with bibliometric analysis.

The purpose of this study is to make a holistic summary of the articles published in the field of Legal Medicine/Forensic Science through bibliometric methods, determine the top cited publications in the field, and to determine the most active journals and especially trend topics. The articles published in the field of Legal Medicine between the years 1975 and 2018 were downloaded from the Web of Science index and were analyzed using bibliometric methods. The correlations between the number of publications of the countries and the Gross Domestic Product (GDP), and the Gross Domestic Product per capita (GDP PPP) values was analyzed using the Spearman's correlation coefficient. The number of articles to be published in the field of Legal Medicine between the years 2019 and 2022 was estimated with linear regression analysis. The results showed that there were totally 38845 articles published in the field of Legal Medicine. Regression analysis results indicate that it will exceed 2500 publications after 2022. The most productive countries in the field of Legal Medicine were the USA (12.448, 32.045%). A high correlation was found between legal medicine publication productivity and GDP and GDP PPP (r = 0.726, p < 0.001; r = 0.703, p < 0.001). As for the collaboration between countries, analysis results showed that the network web indicated the most important factor as the geographical location. This study will provide important information to a forensic scientist (a doctor, academic, and practitioner).

Research Progress on Forensic Palynology and Its Application in Forensic Science / 法医学杂志

Forensic palynology is to apply palynology to the field of forensic science, using pollen and spores to solve issues in juridical practice, such as civil and criminal issues. Sporopollens have a small size, wide distribution, diverse morphology, can be easily transferred, have durability, and is not easily noticed. It can provide strong investigation and related evidence for case detection as good trace evidence. The application of palynology in forensic science has achieved certain success, but it is underutilized in most countries. This paper analyzes the evidence value provided by sporopollen, collection of the sporopollen samples, the progress in detection technology and challenges ahead, based on the biological characteristics of sporopollen, combined with recent successful cases in forensic science, to comprehensively discuss the research progress in forensic palynology and its application prospects in forensic science.

Hydrocarbon and Fatty Acid Composition from Blowfly Eggs Represents a Potential Complementary Taxonomic Tool of Forensic Importance.

One of the most important contributions of forensic entomology is to assist criminal expertise to determine the postmortem interval, which depends on the duration of the immature stages of insects of forensic interest. On the other hand, the time of development of the different stages varies according to the species; therefore, its identification is essential. Currently, few studies have investigated the use of cuticular hydrocarbons, and none regarding fatty acids, as complementary taxonomic tools to expedite species identification. Therefore, we evaluated whether cuticular hydrocarbons together with fatty acids of eggs of flies of the family Calliphoridae, main group of forensic interest, can be used to distinguish species. The analyses were performed by chromatographic techniques. The results show that there are significant differences between the composition of cuticular hydrocarbons and fatty acids between species and, therefore, they can be used to provide a complementary taxonomic tool to expedite the forensic expertise.

Forensic palynology and the search for geolocation: Factors for analysis and the Baby Doe case.

First used over 50 years ago, forensic palynology is an important tool for law enforcement agencies. In most countries that use forensic palynology, microscopic pollen grains and spores are traditionally used in criminal investigations to link suspects to crime scenes or items. While still underutilized in many parts of the world, forensic palynology is increasingly being used to determine the region of origin, or geolocation, for persons and items of interest. Drawing upon the experience of the authors using trace pollen and spores to geolocate forensic samples, the types, methods, and variables of this type of analysis are discussed and demonstrated using the Baby Doe case from Massachusetts, USA as a case study. This is not an exhaustive list and every forensic sample is unique so the methods and experience presented here are intended to be a guide for future forensic and anti-terrorism investigations as forensic palynology becomes more commonplace in law enforcement agencies around the world.

Multi-Modal Compositional Analysis of Layered Paint Chips of Automobiles by the Combined Application of ATR-FTIR Imaging, Raman Microspectrometry, and SEM/EDX.

For the forensic analysis of multi-layered paint chips of hit-and-run cars, detailed compositional analysis, including minor/trace chemical components in the multi-layered paint chips, is crucial for the potential credentials of the run-away car as the number of layers, painting process, and used paints are quite specific to the types of cars, color of cars, and their surface protection depending on the car manufacturer and the year of manufacture, and yet overall characteristics of some paints used by car manufacturers might be quite similar. In the present study, attenuated total reflectance-Fourier transform infrared (ATR-FTIR) imaging, Raman microspectrometry (RMS), and scanning electron microscopy/energy-dispersive X-ray spectrometric (SEM/EDX) techniques were performed in combination for the detailed characterization of three car paint chip samples, which provided complementary and comprehensive information on the multi-layered paint chips. That is, optical microscopy, SEM, and ATR-FTIR imaging techniques provided information on the number of layers, physical heterogeneity of the layers, and layer thicknesses; EDX on the elemental chemical profiles and compositions; ATR-FTIR imaging on the molecular species of polymer resins, such as alkyd, alkyd-melamine, acrylic, epoxy, and butadiene resins, and some inorganics; and RMS on the molecular species of inorganic pigments (TiO2, ZnO, Fe3O4), mineral fillers (kaolinite, talc, pyrophyllite), and inorganic fillers (BaSO4, Al2(SO4)3, Zn3(PO4)2, CaCO3). This study demonstrates that the new multi-modal approach has powerful potential to elucidate chemical and physical characteristics of multi-layered car paint chips, which could be useful for determining the potential credentials of run-away cars.

Promoting the qualitative research approach in the discipline of forensic and legal medicine: Why more qualitative work should be promoted and how that can be achieved.

Much of the existing published research in Forensic and Legal Medicine is based upon the quantitative approach, which is derived from the positivist paradigm and generally employs pre-determined data collection tools to gather data for statistical analysis with a view to testing hypotheses. It must always be remembered that clinicians are concerned not only with diagnosing and treating medical problems in a vacuum, but rather they must empathise with patients and provide care in a holistic fashion. Too narrow a focus on the quantitative approach to research will significantly limit the evidence base upon which the Discipline of Forensic and Legal Medicine can develop. Wider adoption of the qualitative approach, which stems from the interpretivist paradigm and harnesses research methods that allow in-depth exploration of the meaning and understanding that individuals ascribe to the world around them, would generate rich insight in to patients' experiences of forensic healthcare, which could be utilised to advance quality improvement. This article outlines how qualitative research can benefit the discipline, identifies barriers to its use and suggests brief, targeted solutions.

Surface coatings including fingerprint residues can significantly alter the size and shape of bloodstains.

When conducting a blood pattern analysis (BPA) the size, shape, distribution, and location of bloodstains found at a crime scene may be critical in forming a hypothesis as to what transpired during a bloody event. Prior studies have demonstrated that the size and shape of a bloodstain on a smooth surface are determined from impact dynamics and to a lesser degree by the target material itself. Yet, these studies have relied on clean surfaces, and it is unclear whether the presence of microscopic coatings and residues could significantly alter the size or shape of the dried stain. Here, in the present work, experiments are conducted to demonstrate that various coatings, such as the sebaceous residue from a latent fingerprint, can dramatically alter the size and shape of the stain from the moment of impact through the drying process. These experiments also highlight that a drop impacting a tilted superhydrophobic-coating glass substrate can cause the blood drop to completely recoil without leaving a stain. Relying on a combination of high-speed and time-lapse photography, the specific stages in the stain evolution responsible for the deviations from the current models are identified. At a relatively low impact velocity, the stain sizes on the coated glass surfaces were 35-72% smaller than on the clean glass surface. At a higher impact velocity, the stains on the coated surfaces were not only smaller, but also contained drop spatter around the primary stain that was not observable in the absence of the microscopic coatings. The reduction in bloodstain size did not appreciably change when a chemical was added to deactivate the anticoagulant and allow the blood to clot.

Memory at the Sharp End: The Costs of Remembering With Others in Forensic Contexts.

In many applied contexts where accurate and reliable information informs operational decision-making, emergency response resource allocation, efficient investigation, judicial process, and, ultimately, the delivery of justice, the costs of unfettered conversational remembering can be high. To date, research has demonstrated that conversations between co-witnesses in the immediate aftermath of witnessed events and co-witness retellings of witnessed events often impair both the quality and quantity of information reported subsequently. Given the largely negative impact of conversational remembering on the recall of both individual witnesses and groups of witnesses in this context, this review explores the reasons why these costs occur, the conditions under which costs are exacerbated, and how, in practical terms, the costs can be reduced in order to maximize the accuracy and completeness of witness accounts.