Forensic Sciences

Background/Objectives: Over the past few decades, controlled substance abuse in drug-facilitated sexual assaults (DFSAs) has significantly increased worldwide, leading to an urgency to develop rapid and selective drug detection methods for field use (i.e., on-spot detection). Currently, techniques for detecting DFSA drug-associated samples are laborious and require skilled personnel to analyze/interpret the results. Moreover, most DFSA-associated drugs have a short half-life, making them more challenging to detect promptly. For instance, the timely detection of gamma-hydroxybutyrate (GHB) has been of ultimate concern for decades due to its fast elimination from the body. This study describes the development of a fluorescent ionic liquid nanosensor that can be used to rapidly detect GHB in the field. Methods: Trihexyltetradecylphosphonium fluorescein (THP₂FL) ionic liquid was synthesized and evaluated for its potential application in detecting GHB. THP₂FL nanoparticles in deionized water were synthesized with a size of 199 nm by a reprecipitation method. Results: The addition of GHB to THP₂FL nanoparticles resulted in up to a 60% increase in fluorescence intensity and a 79% increase in absorbance. These results suggest potential applications for using the fluorescent THP₂FL nanoparticles to detect GHB. The sensor’s selectivity was tested on compounds structurally similar to GHB, and the results showed that 1,4-butanediol (a precursor of GHB) is a potentially interfering species. Conclusion: This fluorescent technique allows for field deployable sensors, which would benefit screening GHB onsite. Full article

Background/Objectives: Traditional diagnostic criteria for SBS include subdural, subarachnoid, and retinal hemorrhages. While intentional shaking is a known cause, the potential for similar forces acting on the head resulting from accidental trauma has not been fully explored. This study investigated the biomechanical forces on a model infant’s head during improper handling to determine if such forces could contribute to SBS without malicious intent. Methods: A realistic silicone infant model was equipped with an inertial measurement unit (IMU) to quantify head accelerations during two conditions: (1) placement of the infant model on a table with the head unsupported, and (2) manual shaking at maximum effort by 2 participants holding the model by the torso. Peak head accelerations were recorded for both conditions, and the results were analyzed for comparative assessment of the forces involved. Results: The average peak head acceleration when placing the infant model on a table with the head unsupported was +31,000 ± 7000 mg, with a range of +19,000.00 to +43,000 mg across trials. The average peak head accelerations during maximum effort shaking were significantly lower than placing the infant on the table, averaging 11,000 ± 10,000 vs. 31,000 ± 7000 mg, p < 0.0001). There were no significant differences in head accelerations between participants when placing the infant model on the table with the head unsupported (p = 0.89) nor with shaking the baby with maximum effort (p = 0.96). Conclusions: The study highlights that even accidental non-recommended handling of infants can result in high G-forces to the head, potentially leading to injuries similar to those observed in SBS. These findings highlight the necessity of supporting an infant’s head during handling and warrants caution against prematurely attributing physical abuse in SBS cases without considering unintentional causes. Full article

Background: The identification of body fluids collected from crime scenes is crucial for determining the type and nature of assaults and for advancing the resolution of crimes. Objectives: The primary aim of this study was to investigate tissue-specific DNA methylation markers that can effectively distinguish buccal samples from blood, semen, and vaginal epithelial tissue. Methods: We screened various markers and selected four genomic locations for further analysis. Genomic DNA was extracted from tissue samples, followed by bisulfite conversion, locus-specific polymerase chain reaction (PCR) amplification, and pyrosequencing. Results: Four loci—cg-9652652, cg-11536474, cg-3867465, and cg-10122865—along with several adjacent CpG sites, were found to be hypermethylated in buccal samples compared to other tissue types. The difference in DNA methylation of buccal samples was statistically significant (p < 0.0001) compared to other tissues, indicating the potential usefulness of these loci for forensic tissue identification. Two additional studies were conducted: (a) a species specificity study and (b) a mixture study involving two different tissue types. The species specificity study showed that the primers used in the assay were specific to primates and humans. They did not amplify five non-primate samples, while the two primate samples—chimpanzee and rhesus—provided usable methylation data. The mixture study involved DNA from two different tissues—buccal samples and semen—combined in varying proportions. The results showed a decrease in the overall percentage of DNA methylation at the locus cg-9652652 as well as five adjacent CpG sites when the amount of buccal cell DNA in the mixture was reduced. Conclusion: The specificity of the primers and the significant differences in percent DNA methylation between buccal cells and other tissues make these markers excellent candidates for forensic tissue identification. Full article

The calcaneus is very useful in archaeological contexts where human remains may be commingled. When DNA is impossible and the context is commingled, non-metric traits of the calcaneus may be used to identify phenotypical differences between human remains. Background/Objectives: We compared the prevalence of several calcaneal non-metric traits of pre-Hispanic and modern inhabitants of the Canary islands in order to (1) test the skeletal variation between pre-Hispanic and modern (17–18th century) Canarian samples and (2) gather information on biological and lifestyle differences between the samples using the calcaneal bone. Methods: We used a total of 364 calcanei (164 modern Canarian [72 left and 92 right] and 200 pre-Hispanic Canarian [92 left and 108 right] calcanei) and available non-metric traits to show differences between modern and pre-Hispanic Canarian population samples. Results: Our results highlight that some particular activity traits were common among the pre-Hispanic sample, while other traits, such as articular facet type Ib and the medial root of the inferior extensor retinaculum, show similar frequencies between pre-Hispanic and modern samples, which may indicate a genetic proponent influencing these similarities. Conclusions: Our results suggest that at least two traits, facet type Ib and the medial root of the inferior extensor retinaculum, may be influenced by genetics due to the persistence in modern samples despite the change of lifestyle between pre-Hispanic and modern Canarians. Full article

(1) Background: Scavenger activity can pose significant challenges in forensic investigations. When examining damage on a victim, forensic investigators must first determine whether the damage resulted from human actions or animal scavenging. Accordingly, knowledge of the scavenger populations inhabiting a specific region and their scavenging behaviors is essential for accurately reconstructing the environmental context of the remains and interpreting associated taphonomic evidence in forensic investigations. (2) Methods: This study investigates the scavenging behavior of bobcats (Lynx rufus), a species native to North America, under controlled experimental conditions. The authors placed the carcasses of seven adult white-tailed deer in an outdoor field in Murfreesboro, Tennessee, and systematically documented the scavenging activities. (3) Results: Bobcats were observed to primarily scavenge soft tissue from the torso, focusing on musculature while generally avoiding bony regions. When unsatisfied with the torso, they shifted attention to the upper limbs, with minimal interest shown in the head or neck. Bobcats also exhibited a tendency to feed in a single area for extended periods, leading to concentrated damage in specific locations on the remains. (4) Conclusions: The findings demonstrate that bobcats can significantly influence the postmortem conditions of remains, producing characteristic patterns of modification. Recognizing these patterns is essential for forensic investigators and examiners when interpreting scavenger-related alterations in forensic contexts. Full article

The decision to remove a bullet from a gunshot victim depends on its location and associated medical risks, with surgical extraction often not indicated. Radiological imaging plays a vital role in assessing gunshot wounds and locating bullets, and it is essential in both clinical and forensic contexts. This narrative review examines the use of computed tomography (CT) for virtual bullet analysis, providing insights into shape, design, fragmentation, and material composition. Traditional 2D X-ray imaging, though commonly used, has limitations in accurately assessing caliber and position due to magnification and its 2D nature. In contrast, CT scans generate 3D reconstructions for detailed and precise examination, overcoming challenges such as metal artifacts with techniques such as extended Hounsfield unit (HU) reconstructions. These methods enhance the visualization of metal objects, allowing for better analyses of lodged bullets. Dual-energy CT further differentiates materials, such as lead and copper, using HU value differences at two energy levels. These advancements enable the virtual classification, shape analysis, and material identification of bullets in forensic investigations, even when the bullet remains in the body. As CT technology progresses, its forensic applications are expected to improve, providing more accurate and comprehensive differentiations of bullet types in future cases. Full article

Lithium is used as a medication in the treatment of bipolar disorder. Lithium has a narrow therapeutic index, and fatal intoxications have been described. The therapeutic drug monitoring of lithium is routinely performed in serum. Serum is commonly unavailable in forensic postmortem analysis, where whole blood is the matrix of choice. In this study, an inductively coupled plasma mass spectrometry (ICP-MS) method was developed and validated for the quantification of lithium in postmortem whole blood. Sample preparation consisted of a 100-fold dilution with acid and required only 40 µL of blood. Carry-over was deemed appropriately reduced with a rinse solution containing 5% hydrochloric acid. A nebulizer gas flow rate of 1.15 L/min showed a sufficient improvement of lithium sensitivity while simultaneously minimizing the background. Germanium was determined to be the most optimal internal standard. The method was validated in terms of linearity, accuracy, precision, and lower limit of quantification. Linearity was demonstrated within the analytical measurement range of 0.10–1.5 mmol/L. The method showed acceptable precision and accuracy, with a total coefficient of a variation ≤2.3% and accuracies ranging from 105 to 108% at all concentrations in the quality control samples. The final method was applied to postmortem blood from 103 consecutive autopsy cases and demonstrated robustness by low intermediate precision and high and consistent recovery of the internal standard. Full article

Background: Chemical odor profiling within forensic entomology is an emerging tool given its potential for species identification and larval aging and its ability to identify decomposition stages. A volatile analysis of larval masses across species of distinctive developmental stages was carried out with extraction techniques to identify odor signatures. However, it is unknown how larval sample handling (i.e., live samples in research vs. hot-water-killed samples in casework) affects odor signatures or the possibility of obtaining relevant volatiles from a single larva. Method: This study utilized solid-phase microextraction (SPME) with gas chromatography–mass spectrometry (GC/MS) for the analysis of odor volatiles emanating from single larval samples of Cochliomyia macellaria. Fifty (50) larvae (25 live; 25 boiled) were analyzed. Results: The SPME-GC/MS method allowed for odor volatile detection from a single maggot regardless of the sample handling group. The main compounds identified across both groups included those previously reported as emanating from larvae and decomposition substrates. When comparing treatments, the boiled larval samples had a 6-fold decrease in compound abundance compared to the live samples. The identified odor volatiles observed in the hot-water-killed treatment group included indole, p-cresol, and phenol. Conclusions: These results suggest that the handling technique impacts odor detection. Additionally, the heterocyclic aromatics and alcohols identified in the boiled samples are potentially odor markers of a higher intrinsic nature to the maggot rather than a cross-transfer from the decomposition substrate given their survival post elevated temperature treatment. This work shows the plausibility of carrying out an odor analysis of a single maggot following both common research and casework handling practices. Full article

Background: The COVID-19 pandemic significantly disrupted forensic science, exposing vulnerabilities and introducing unprecedented challenges. Five years later, its impact persists, necessitating ongoing adaptations in forensic practice. This study examines key transformations, persistent issues, and emerging challenges in forensic science post-pandemic. Methods: A critical analysis of forensic science’s response to the pandemic was conducted, focusing on operational disruptions, methodological advancements, educational shifts, and technological integration. Results: Forensic operations faced delays due to case backlogs, restricted in-person work, and postponed court proceedings. Forensic pathology evolved with increased reliance on molecular autopsy techniques to clarify COVID-19-related deaths. Educational methods shifted toward virtual learning, prompting discussions on standardized digital training. Additionally, artificial intelligence and automation gained prominence in forensic investigations, enhancing crime scene analysis and predictive modeling. Discussion: While forensic science demonstrated adaptability, challenges remain in international collaboration, resource distribution, and professional training. The pandemic accelerated technological integration but also raised ethical and procedural concerns, particularly regarding AI applications in legal contexts. Virtual learning innovations necessitate further development to ensure competency in forensic training. Conclusions: Forensic science continues to evolve in response to post-pandemic realities. Addressing gaps in cooperation, technology implementation, and training will be crucial to strengthening the field. By assessing these changes, this study underscores forensic science’s resilience and adaptability, offering insights into its future trajectory amid ongoing challenges. Full article

Background: Accurately determining the post mortem interval (PMI) is critical in forensic investigations to reconstruct the sequence of events leading up to and following death. Traditional methods (e.g., observing livor mortis, rigor mortis, and using temperature-based models) have limitations due to their empirical nature and susceptibility to environmental variables. The objective of this study was to assess the potential of a novel portable device, the Fisic Medimate™ system, for estimating PMI through the analysis of the potassium/sodium (K+/Na+) ratio in vitreous humor. Method: Vitreous humor samples were collected from pigs at various intervals up to 44.5 hours post-mortem. These samples were analyzed using the Fisic Medimate™ system to determine the K+/Na+ ratio. The analysis was conducted at different time points to establish a relationship between the K+/Na+ ratio and PMI. Results: The results indicated a log-linear relationship between the K+/Na+ ratio and PMI for periods up to 31 hours, with normal residuals. This relationship was observed across all samples, suggesting that the method provides reliable and consistent data. Conclusions: This method offers a rapid and portable solution for PMI determination, providing valuable data within minutes directly at the crime scene. While these findings suggest potential for on-site forensic applications, further validation under real-world conditions is required to confirm its broader applicability. Full article

Background: In forensic investigations, the postmortem interval (PMI) is still mainly determined using pathological analysis. There have been many scientific efforts to identify alternative methods of PMI determination, which may be applied to future forensic practices. Methods: Considering the ethical implications and the availability of tissue samples for PMI experiments, we used human blood samples stored at three temperatures to mimic different environmental conditions, testing them over a period of 10 days post-sampling. These samples were biochemically tested for specific blood biomarkers, glucose (Glu) and lactic acid (Lac), to determine their potential as PMI biomarkers. Then, a mixed-effect mathematical model was applied to the data related to time- and temperature-dependent concentration changes of both biomarkers followed by additional computer-simulated models to refine the PMI estimates based on each of the biomarker concentration changes. Results: Herein, we present this alternative method of PMI estimation based on the biochemical testing of blood samples that could potentially be collected at a crime scene using biochemical blood biomarkers Glu and Lac, which are mathematically modelled and refined with time- and temperature concentration changes. Conclusions: While there is still much forensic science required to validate any alternative PMI methods, this study shows that there are other cross-disciplinary methods of PMI determination that warrant further exploration. Full article

Contemporary human preservation technologies aim to preserve the structure of the body—and especially the brain—after legal death. Although it has not yet been demonstrated, some believe that this may act as a bridge to future medical technologies that could allow for the recovery of life, if this ever becomes feasible and humane. However, current death investigation practices impose two significant obstacles to high-quality preservation. The first and most common is ischemic delay—the period between legal death and initiation of preservation while the death is investigated, during which brain tissue progressively degrades. The second is involuntary autopsy, where tissue disruption can severely compromise preservation quality. Through analysis of legal precedents and the ethical principles of bodily autonomy, non-discrimination, and potential preservation of life, we argue that individuals should be allowed a way to prevent both ischemic delay and autopsy from affecting the quality of their preservation. We explore potential avenues to implement a right to immediate preservation, including administrative, legislative, and judicial approaches, aimed at balancing this right with the societal interest in performing death investigations. This narrative review has implications for individual autonomy, public policy, and the legal framework surrounding death investigation in the context of emerging preservation technologies. Full article

Background: The main objective of this study was to carry out an online questionnaire in order to assess dentists’ knowledge and perception of dental materials submitted to high temperatures, helping to clarify and raise awareness of possible gaps in the area of forensic dentistry, especially in human identification. Results: Out of a total of 272 respondents, there was a greater influx of responses from countries such as Portugal and Brazil, the majority being female (66.3%), with an average age of 39 years. Most dentists consider complete clinical records to be extremely important. In addition, professionals with less experience provide fewer models in releasing their clinical records. In the case of dental materials, dentists consider composite resin and glass ionomers to be more susceptible to changes in shape and colour, while amalgam is considered the most stable, followed by ceramic and metal-ceramic crowns. On the other hand, dentin is considered more susceptible to colour changes than enamel. Enamel is seen by most professionals as resistant, undergoing few changes in shape at high temperatures. Conclusions: The opinion of the surveyed dentists on this subject is broadly in line with the existing literature. The only observed differences were related to exposure time and enamel resistance, since they assume that enamel is more resistant, and dentin is more vulnerable. Full article

A novel method for the development of fingerprints in environmentally friendlier conditions and on porous surfaces with 1,8-diazafluoren-9-one (DFO) is reported herein. DFO, a fluorescent dye was formulated in glacial acetic acid, methanol, and a minimum amount of methylene chloride. The DFO reacted with amino acid components of latent prints, resulting in a fluorescent species that was visualized under daylight, UV light at 254 nm, 365 nm, and LED at 395–405 nm. The developed prints were photographed using iPhone 11 and IOS 17.4.1. The fluorescent spectra of the species resulting from DFO’s reaction with the amino acid glycine and the wavelengths of maximum excitation (λ_ex = 470 nm) and emission (λ_em = 585 nm) were also reported. The method is suitable for forensic laboratories. Full article

Miscarriages of justice led to concerns that forensic science reports were prosecution-biassed and led to elementary errors of probability. The European Network of Forensic Science Institutes (EFNSI) and other institutes developed standards requiring reporting of the probability of evidence under all hypotheses (usually prosecution and defence hypotheses) with the likelihood ratio (LR). $LR={\displaystyle \frac{p\left(E|H_p\right)}{p\left(E|H_d\right)}},$ values > 1, being probative for a prosecution hypothesis. In elementary two-variable conditional probability theory (Baye’s theorem), the LR is also an updating factor which multiplies the odds of guilt for each item of evidence considered. Although this is not true for multiple-variable probability theory, the value of the LR as a valid measure of evidential probity remains. Forensic scientists are experts in evidence and should not stray into the role of the Court to consider the probability of the hypotheses given the totality of the evidence: $p\left(H_p{,H}_d|,E_1,E_2\dots E_n\right).$ Medical experts may be required to assist the court with diagnoses (the hypothesis), but this privilege is balanced by vigilance that experts do not stray beyond their expertise. A narrow interpretation of expertise hinders the evaluation of the evidence under hypotheses adjacent to the area of expertise. This paradox may be overcome by experts declaring competence in areas adjacent to their main area of expertise. Regulatory bodies do not currently require medical experts to adhere to EFNSI guidelines in evaluative reporting. Legal opinion is divided on whether probability theory can be applied to cases requiring medical expertise. Medical experts should, in their reports, clearly separate evaluating the probability of the evidence (where evaluative reporting should apply) and evaluating the probability of hypotheses where methodology should be prioritised over opinion. The reckless misapplication of elementary probability theory, typically transposing conditional probabilities or neglecting prior odds, may lead to the jury being misled into believing posterior odds of guilt are many orders of magnitude greater than reality. Medical experts should declare training in elementary probability theory. Inaccurate probabilities are a joint enterprise between all who inform or advise the jury, so all must be trained in elementary probability theory. Full article

Teeth are highly durable and useful in forensic identification and studying the impact of environmental factors could aid forensic investigations. Accurate post-mortem interval (PMI) estimation using dental evidence is critical in legal contexts, it requires further exploration. Aims: This study included a scoping review investigating macroscopic and microscopic changes in teeth in various simulated environments (Part 1) and an experimental study assessing changes in teeth and restorations exposed to distilled water, saline water, acidic soil, and alkaline soil (Part 2). Methods: The scoping review analysed publications from five databases using keywords such as ‘Teeth’, ‘Dental’, ‘Water’, ‘Soil’, ‘Acid’, and ‘Forensic.’ The experimental study involved 40 human teeth photographed before and after a 90-day exposure period to record shade variations and macroscopic changes. Results: Part 1: Twenty-six relevant articles from 10 countries (1987–2022) were reviewed, with most focusing on human teeth (77%), unrestored teeth (54%), macroscopic changes (46%), and high-temperature environments (53%). Part 2: Teeth in distilled water (G1) showed no shade variation. In saline water (G2), 60% of teeth decreased in shade. In acidic soil (G3), 40% showed an increased shade, while 50% showed a decreased shade. In alkaline soil (G4), 70% of teeth showed an increased shade. Restorations exhibited minimal changes across environments. Conclusions: Studies on the macroscopic changes because of high temperature on teeth and dental restorative material are popular. Teeth exposed to alkaline and acidic soil showed the most changes in the structure. Full article

Background—Endomyocardial fibrosis (EMF) is a chronic restrictive cardiomyopathy endemic to tropical and subtropical regions, characterized by fibrotic thickening of the endocardium, predominantly affecting the ventricular chambers. As global migration increases, cases of EMF may emerge in non-endemic areas, posing a diagnostic challenge for healthcare professionals unfamiliar with this condition. Methods—We report the case of a 21-year-old man of African origin who experienced sudden collapse while residing in a reception center for asylum seekers in Apulia, Southeastern Italy. His medical history revealed that one week prior, he had been presented with high fever, chest pain, and asthenia, symptoms initially misinterpreted as influenza by a local physician, leading to antibiotic therapy. Results—The definitive diagnosis of EMF was established post-mortem through histological examination, which identified characteristic endocardial fibrosis. This case exemplifies the re-emergence of neglected tropical cardiac diseases in Western countries due to increased migration from endemic regions. Conclusions—This case highlights the need for heightened clinical awareness among healthcare professionals, particularly in cardiology and primary care, to recognize and manage geographically displaced diseases such as EMF. Implementing enhanced medical education and diagnostic protocols is essential to address the evolving epidemiological landscape and improve early identification of rare but significant cardiac pathologies in migrant populations. Full article

Background: The aging of fly larvae is primarily determined by their temperature-dependent growth rates, a concept widely applied in forensic entomology to estimate the minimum postmortem interval using the accumulated degree day/hour (ADD/ADH) method. Method: This study adapted the same approach for veterinary entomology, offering insights into how accumulated degree day (ADD) can be used to estimate both the number and timing of fly generations in nature. This study details a method for identifying the pupation landmarks of Ch. rufifacies (Macquart) by characterising seven distinct pupal stages over time. Following this, ADD values were calculated for each life stage using developmental data collected from two types of ovine muscle: muscle with fat and muscle without fat, at two temperatures: 24 ± 1 °C for autumn and 30 ± 1 °C for summer, reflecting typical seasonal conditions in southwestern Australia. Results: This study also provided a graphical illustration of how to estimate the number of fly generations emerging during a season, based on daily temperature data from autumn and summer in southwestern Australia for the 2023/2024 period. Conclusions: This approach highlights the value of developmental data and ADD methods in veterinary entomology, offering a robust framework for understanding fly population dynamics for effective myiasis control strategies. Full article