Journal of forensic sciences最新文献

An inexpensive, commercially available doped strontium aluminate phosphor with long-lived afterglow was prepared as a luminescent fingerprint dusting powder suited for challenging, highly patterned substrates; however, prolonged exposure to humidity was found to reduce that powder's affinity for fingermarks. Here, an enhanced preparation for synthesizing that fingerprint dusting powder is presented that prevents powder aggregation and loss of function upon exposure to humid environments. This was achieved by introducing a flow regulator during synthesis: hydrophobic silica SIPERNAT® D10 or SIPERNAT® D17. Increasing the hydrophobicity of the powder prevents aggregation by inhibiting the uptake of water, thereby improving the material's flow dynamics and transfer behavior from brush to fingermark. The angle of repose and flow characteristics made by the modified powders were quantified, with excellent affinity for fingermarks observed, even after being stored under 85% (±5%) humidity for 4 weeks. A preliminary comparison of the performance of the modified hydrophobic powders relative to the unmodified precursor revealed that more of the SIPERNAT® treated powder typically adhered to fingermarks while simultaneously imparting less background development. In addition, fewer clumps of particulate were observed in the developed fingermarks after addition of a hydrophobic flow regulator. This technical report outlines the updated method for synthesizing the fingerprint powder, with summarized flow performance results, and a demonstration of the modified powder's affinity for simulated fingermark evidence.

In the last decade, the market share and user base of social media applications have witnessed significant growth. However, this surge in popularity has inadvertently drawn the attention of criminals aiming to exploit these platforms for illicit activities. The forensic examination of these applications emerges as a pivotal avenue for uncovering valuable insights into criminal behavior and identifying suspects. Discord, a social media platform, has become a significant focal point for such illicit activities. In this paper, we examine the remnants of Discord on both Windows and Linux operating systems, employing storage, memory, and network analysis techniques to review the remnants of Discord. Our investigation reveals a range of crucial artifacts that have been successfully recovered across all three areas of analysis, including login and payment details, chat history, account information, and much more. Collectively, these artifacts constitute a valuable resource for forensic investigations, allowing the reconstruction of most of the user's activity.

Due to the complex nature of the chemical compositions of ignitable liquids (IL) and the interferences from fire debris matrices, interpreting chromatographic data poses challenges to analysts. In this work, artificial intelligence (AI) was developed by transfer learning in a convolutional neural network (CNN), GoogLeNet. The image classification AI was fine-tuned to create intelligent classification systems to discriminate samples containing gasoline residues from burned substrates. All ground truth samples were analyzed by headspace solid-phase microextraction (HS-SPME) coupled with a gas chromatograph and mass spectrometer (GC/MS). The HS-SPME-GC/MS data were transformed into three types of image presentations, that is, heatmaps, extracted ion heatmaps, and total ion chromatograms. The abundance and mass-to-charge ratios of each scan were converted into image patterns that are characteristic of the chemical profiles of gasoline. The transfer learning data were labeled as “gasoline present” and “gasoline absent” classes. The assessment results demonstrated that all AI models achieved 100 ± 0% accuracy in identifying neat gasoline. When the models were assessed using the spiked samples, the AI model developed using the extracted ion heatmap obtained the highest accuracy rate (95.9 ± 0.4%), which was greater than those obtained by other machine learning models, ranging from 17.3 ± 0.7% to 78.7 ± 0.7%. The proposed work demonstrated that the heatmaps created from GC/MS data can represent chemical features from the samples. Additionally, the pretrained CNN models are readily available in the transfer learning workflow to develop AI for GC/MS data interpretation in fire debris analysis.

Skeletal evidence usually constitutes the only source of information to interpret lesion patterns that help to clarify the circumstances surrounding death. The examination and interpretation of bone trauma are essential to the application and utility of anthropology as a forensic science. When discussing the effect of gunshot wounds in bone, it becomes imperative to differentiate between short and long-distance injuries based on clear, distinct, and observable signs. To contribute to the debate, our focus is directed toward the external analysis of the so-called circumferential delamination defect (CDD) as an observable proxy for close-range shooting (≤30 cm) and contact gunshot wounds in the skull. In the context of known extrajudicial killings, in which the perpetrators used short 9 × 19 FMJ ammunition in a close-range shooting, instances of CDD have been documented. Empirical evidence reinforcing the causal relationship between CDD and close-range shootings is presented. Elements’ characteristics of firearm residues were also found in remains buried for up to 30 years. Primarily, this work shows that the concentrations of gunshot residues (Pb, Ba, and Sb) resemble those observed in fresh corpses with the same gunshot wound (GSW). Moreover, the correlation observed between CDD and gunshot residues, where the likelihood of CDD increases the closer to the head and the more perpendicular the shot angle is, reinforces CDD as a pivotal discriminatory factor in the skeletal evidence of short-range or contact shot. This research contributes to the field of forensic anthropology by providing fundamental insights into the etiology of CDD and its practical application.

Mitragyna speciosa, commonly known as kratom, is a narcotic plant that is used for its unique mood-enhancing and pain-relieving effects. It is marketed throughout the United States as a ‘legal high’ and has gained popularity as an alternative to opioids. However, kratom's increasing involvement in accidental overdoses, especially among polydrug users, has prompted warnings from the Drug Enforcement Agency (DEA) and the Food and Drug Administration (FDA). Despite these warnings, kratom remains legal federally, although it is banned in six states. This legal disparity complicates monitoring and enforcement efforts in states where kratom is illegal. Common forensic techniques using morphology or chemical analysis are beneficial in some instances but are not useful in source attribution because most seized kratom is powdered and the alkaloid content of samples can vary within products, making sourcing unreliable. This study focused on developing a DNA barcoding method to access sequence variation in commercial kratom products. It evaluated the utility of one nuclear barcode region (ITS) and three chloroplast barcode regions (matK, rbcL, and trnH-psbA) in assessing sequence variation across commercially available kratom products. Novel polymorphisms were discovered, and the ITS region showed the greatest variation between samples. Among the 15 kratom products tested, only two haplotypes were identified across the four barcoding regions. The findings highlight the potential of DNA barcoding as a forensic tool in the traceability and enforcement against illegal kratom distribution. Nonetheless, the limited haplotypic diversity points to a need for further development and expansion of the M. speciosa DNA sequence database.

Two chemists employed a three-device rapid screening “toolkit” consisting of a handheld Raman spectrometer, transportable mass spectrometer, and portable Fourier transform infrared (FT-IR) spectrometer at an international mail facility (IMF) satellite laboratory to examine unknown (unlabeled/mislabeled) products for the presence of active pharmaceutical ingredients (APIs). Phase I of this project previously demonstrated that this toolkit was the most effective collection of instruments for identifying APIs in product types collected at IMFs during a nationwide mail blitz and Phase II of this project previously demonstrated that results generated using the toolkit during a satellite laboratory pilot program were as reliable as those generated by a full-service library when two or more of these instruments identify an API. This study (Phase III) described the results of the satellite laboratory toolkit during production mode and encompassed the period ranging from June 2021 through December 2022. During this study, a total of 858 products were examined on-site at the IMF. The satellite laboratory yielded conclusive results for 726 (84.6%) products, which were used to support regulatory action, and identified 132 (15.4%) products that required additional full-service laboratory analyses due to inconclusive results. The satellite and full-service laboratory verified/confirmed at least one API/related substance in 617 (71.9%) products. A total of 709 APIs/related substances were found in the 617 products, and 202 of these 709 compounds were unique/different. Overall, during Phases I through III of this program, 350 different substances have been identified in products collected at IMFs.

High rates of suicide continue to plague the modern world, with clinicians, researchers, and policymakers working urgently to ameliorate what has been recognized as a worldwide public health crisis. Under American Law, individuals- including health care providers, could generally not be held liable for causing the suicide of another person. This article presents a review of suicide law in the United States in the context of a recent civil case in which a physician with expertise in mental health was sued for the death of an ex-partner who committed suicide in his home. Historical events and landmark legal cases spanning the 15th century to now are examined and presented as a narrative review to inform society and mental health clinicians a-like towards interpreting the changing medical-legal landscape. As modern advances in science continue to discern the critical biopsychosocial factors that contribute to the act of suicide, there is an inevitably growing concern that suicide may no longer be an incomprehensible nor irrational event as has been assumed for centuries. Thus, it may be considered that individual with expertise and qualification to treat a group of individuals at higher risk of suicide (severe mental illness) may be subject to a different standard than the average individual. This article seeks to present a complex matter where no simple or broad-sweeping conclusions can yet be drawn, however remains a critically important matter for mental health clinicians.

Researchers have observed that rainfall may re-initiate decomposition in desiccated tissue; however, no conclusive research-based evidence exists on the specific effects of rehydration on decomposition. Therefore, this study aimed to assess the effects of artificial rehydration on the progression of decomposition following the advanced stage of decomposition. Twelve adult pig cadavers (8 experimental; 4 controls) were placed in the central Highveld of South Africa during cooler (April–July 2021) and warmer (August–November 2021) months. Decomposition was scored approximately biweekly to obtain the total body score, and accumulated degree days (ADD) were calculated for each pig. All pig cadavers were covered by chicken wire cages with transparent tarps to control for natural rehydration and scavenging. Once the experimental pig cadavers reached a three-visit stasis in the advanced phase of decomposition, they were artificially rehydrated, and changes in the progression of decomposition between the control and experimental groups were plotted (ADD against TBS) for observation. The rehydrated experimental pig cadavers showed re-initiation of decay and insect re-colonization, while the control cadavers mainly remained in a state of stasis with insect activity ceased altogether. Greater cadaver decomposition islands and a color change post-rehydration were also noted in some experimental cadavers. This supports the need for future research on the impact of rehydration, including associated soil moisture on decomposition rates, progression, and invertebrate colonization, which will enhance our understanding of the effects these environmental factors have on the accuracy of post-mortem interval estimation.

Highways, the lifeline of the Brazilian economy, transport approximately 75% of the country's economic activity, highlighting its importance. However, professional drivers, accustomed to long daily journeys, make use of tablets widely available in Gas Station, which are known as “Rebites,” which could contain a mixture of legal and illegal compounds. Thus, this study aims at the chemical characterization of these through different analytical methods. Initially, we performed a comprehensive screening of compounds present in seven samples collected across the country using high-resolution mass spectrometry (HRMS). The findings revealed caffeine as the main compound, alongside theophylline, lidocaine, and clobenzorex, among others. In the next step, we employ quantitative nuclear magnetic resonance (qNMR) to quantify the caffeine content in the tablets. The results indicated a caffeine concentration ranging between 14% and 31% (m/m), which may imply a daily overdose of this compound from around four tablets. In summary, this investigation provides a chemical characterization of real samples of “Rebites” freely obtained along Brazilian highways. Caffeine emerged as the predominant active compound, with its concentration determined by qNMR analysis. The notable presence of caffeine, combined with other stimulants, depressants, and hallucinogens, underscores the need for strict quality control measures regarding “Rebites” to safeguard public health.

The potential evidential value of male underwear in cases of alleged sexual assault is often overlooked. Male underwear can be a critical item in the investigation of alleged sexual assaults. Body fluids/DNA, which may transfer to the penis during sexual contact, may in turn transfer to the inside front of the underwear, and persist for months or years, provided the underwear are not washed. Here, we demonstrate how the case circumstances drive the sampling strategy of male underwear, in order to maximize the effectiveness of the forensic analysis. Sampling considerations including recovery methods and sampling sequence are discussed, and a methodical examination strategy of male underwear is proposed. To highlight the pertinence of male underwear to the investigation of alleged sexual assaults, three real-life cases are discussed, in which male underwear were examined for multiple body fluids/DNA, and the findings obtained proved evidentially significant. The different cases demonstrate the versatility of male underwear examination in situations, where different body fluids and DNA may transfer based on the specific allegation, and emphasize how targeted sampling can allow the scientist to assess the probability of the findings based on two competing propositions. Accurate sampling strategies are imperative for robust probability assignment in evaluative reporting of scientific findings.