Forensic science international最新文献

Operational forensic laboratories routinely perform immunological assays for detecting various body fluids. The ABAcard® p30 and HemaTrace® immunochromatographic tests from Abacus Diagnostics are used for detecting the p30 enzyme in human semen and human haemoglobin present in blood respectively. In early 2023, manufacturer modifications to the ABAcard® p30 and HemaTrace® tests resulted in a reduction in card size and volume of sample extract used in the recommended protocol. This change in card design and/or the reduced volume of sample extract may alter the sensitivity of the test. This study established and compared the limit of detection (LOD) for the old and newly modified ABAcard® p30 and HemaTrace® test cards. The LOD values showed that the new test cards were approximately 2.4-fold (HemaTrace® test) and 3.4-fold (p30 test) more sensitive than the old cards. Additionally, it was found that the new HemaTrace® test cards were more susceptible to the high dose hook effect. In response to the increased sensitivity, existing data pertaining to the reactivity of these test cards to non-target body fluid and substances warrants re-investigation to ensure positive results are interpreted correctly.

Understanding the factors that influence nitrite degradation in whole blood and developing methods for its stable preservation are crucial for ensuring accurate and reliable forensic identification in cases of nitrite poisoning. This study systematically monitored nitrite degradation and changes in hemoglobin proportions across different initial nitrite concentrations and blood samples. It was revealed that high nitrite concentrations rapidly reduced deoxyhemoglobin levels within the first 15 minutes and subsequently reacted with oxyhemoglobin at a slower rate. Therefore, the proportions of these two hemoglobin forms are key factors in determining nitrite degradation rates. Regarding preservation, the study examined the effects of low temperatures (4°C and −20°C) and various preservatives (potassium ferricyanide, N-ethylmaleimide) on nitrite stability. The results indicate that adding 6.6 g/L potassium ferricyanide can rapidly eliminate all deoxyhemoglobin and reduce oxyhemoglobin proportions to below 60 %, enabling stable preservation of high nitrite concentrations in whole blood for over 30 days at −20°C. The efficacy of potassium ferricyanide was further validated in forensic-acquired postmortem heart blood samples.

Drug-related fatalities in the EU are predominantly associated with opioids. MDMA (Ecstasy) consumption results in fewer lethal intoxications despite its widespread use. This study investigates MDMA-related fatalities, focusing on enantiomer ratios of MDMA and its metabolite MDA to explore the role of metabolism in fatal outcomes. MDMA induces euphoria, increased empathy, and physiological effects such as tachycardia, hypertension, and hyperthermia. Metabolism mainly involves CYP1A2 and CYP2D6, with polymorphism of the latter influencing metabolism rates. Our institute observed several MDMA-related fatalities, which prompted an investigation into the potential role of inefficient drug metabolism in these cases. A novel quantitative chiral analysis method was developed and validated for MDMA, MDA, amphetamine and methamphetamine enantiomers in human blood. Analysis of post mortem blood samples from eleven MDMA-related fatalities exhibited a wide range of concentrations and enantiomer ratios. Variability in R/S MDMA ratios, however, could be linked to the time period of metabolism. Hair analysis revealed high MDMA concentrations in all segments, irrespective of prior drug abuse anamnesis. Therefore, hair analysis may not be suitable for the assessment of past drug use in ecstasy-related fatalities. The results indicated that elevated levels of the MDMA enantiomer are correlated with longer survival times in cases of intoxication. However, there was no clear evidence for slowed MDMA metabolism as a cause of lethal intoxications. While challenges remain due to the diversity of cases, this study contributes valuable insights into ecstasy intoxications, aiding future interpretation of post mortem analysis.

Many methods of ballistic toolmark comparison rely upon comparison using 2D greyscale imaging. However, newly emerging analysis methods such as areal surface analysis now utilise an extra dimension of measurement allowing the surface heights/depths of unique toolmark features to be recorded in a densely populated (x,y,z) array for a 3D/areal quantitative comparative analysis. Due to this step change, the colloquialism in referring to the crater produced at the centre of the primer during firing as a “firing pin impression” has become a misnomer, leading some to believe that this toolmark is produced via a single process, where the critical variable is the condition of the firing pin. Furthermore, current forensic ballistic methodology relies on the microscopic differences between individual fired bullets and cartridge cases produced as a result of the manufacturing process of a particular firearm, in this case “matched toolmarks” confirm a ballistic match to a specific firearm. However, very rarely is it considered that the ammunition itself possesses minute differences produced during manufacture that could affect the ballistic match efficacy. This study examines the discharge process of conventional centrefire ammunition and concludes that the unique toolmarks upon the cartridge primer are definitively produced in two defined stages. This conclusion suggests that the factory loading and quality control tolerances of the cartridge itself should now be considered to be a more significant contributing factor to the production of cartridge primer toolmarks than has previously been accepted.

Hyperspectral imaging (HSI) has become a crucial innovation in forensic science, particularly for analysing bodily fluids. This advanced technology captures both spectral and spatial data across a wide spectrum of wavelengths, offering comprehensive insights into the composition and distribution of bodily fluids found at crime scenes. In this review, we delve into the forensic applications of HSI, emphasizing its role in detecting, identifying, and distinguishing various bodily fluids such as blood, saliva, urine, vaginal fluid, semen, and menstrual blood. We examine the benefits of HSI compared to traditional methods, noting its non-destructive approach, high sensitivity, and capability to differentiate fluids even in complex mixtures. Additionally, we discuss recent advancements in HSI technology and their potential to enhance forensic investigations. This review highlights the importance of HSI as a valuable tool in forensic science, opening new pathways for improving the accuracy and efficiency of crime scene analyses.

Cigarette stubs are commonly encountered trace DNA samples at crime scenes. Standard laboratory practice typically involves direct lysis of the stub for DNA extraction, leading to the co-extraction of DNA-degrading and inhibiting constituents from smoke and tobacco. This process can result in lower-quality DNA profiles. There has been limited focus on developing specific sample processing techniques that minimize these degrading agents and inhibitors before DNA extraction, which could significantly enhance the quality of DNA profiles. This study evaluates a previously established Cell Elution Method (CEM) against the conventional Direct Lysis Method (DLM) for DNA extraction from cigarette stubs. DNA quantity, quality, and subsequent STR profiles were assessed in 80 smoked cigarette stubs, comprising both flavoured and unflavoured types. While CEM exhibited comparable DNA yield from both flavoured (0.17 ng) and unflavoured (0.19 ng) cigarettes, DLM showed significant variability in average DNA yield for unflavoured (0.05 ng) and for flavoured (0.25 ng) cigarettes. Notably, CEM-treated samples demonstrated lower Degradation Index (DI) values compared to DLM-treated ones for both the types of cigarettes. Consequently, STR profiling success rates were higher with CEM, with 95 % of flavoured and 55 % of unflavoured samples yielding informative profiles, compared to 80 % and 0 %, respectively, for DLM. In unflavoured stubs, Amelogenin marker amplification was achieved in 35 % of CEM-treated samples, significantly outperforming the 5 % success rate with DLM. Additionally, CEM resulted in higher average allele recovery rates for both flavoured (58.98 %) and unflavoured (33.41 %) samples compared to DLM. These findings indicate that CEM outperforms DLM in producing higher-quality DNA profiles from cigarette stubs. Thus, CEM can be a choice of method for processing cigarette stub prior to DNA extraction.

Detection of ignitable liquid residues in a fire scene is essential for determining the origin. Although studies are focused on the detection of residues of accelerants depending on time or matrices, the time-dependent effect of the water extinguishing method in a fire has not yet been investigated. Experimental studies are needed to determine how long ignitable liquid residues can be detected in water-extinguished evidence compared to the smothering method. In this study, the effects of both extinguishing methods on gasoline residues were investigated after burning of carpet, sofa fabric, tablecloth, and towel by Solid Phase Micro Extraction- Gas Chromatography/Mass Spectrometry (SPME-GC/MS) technique. Four mandatory and 14 additional compounds were considered to prove the gasoline residue after the monitoring of possible interferences. Results showed that gasoline residues on the burned carpet and sofa fabric samples were successfully detected in both extinguishing methods up to 60 and 30 days after fire exposure, respectively due to multi-layered structures of related substrates. Additionally, the prolonged detection time of the water-extinguishing method made it particularly beneficial for single-layered products like tablecloths, where gasoline residues were found after an hour in this substrate. This is the first study investigating the effects of the extinguishing methods depending on time for textile products, which are the most used materials in houses. In addition, the fact that acrylamide-containing sofa fabric was investigated for the first time and that gasoline residues in carpet samples can be detected up to 60 days makes this study stand out.

Snakebites account for a substantial public health burden in India, contributing to 80 % of global snakebite fatalities. This case series explores the intricacies of two alleged neurotoxic snakebite deaths, delving into the complexities of diagnosing neurotoxic snakebite deaths in India through meticulous medico-legal autopsies. Despite initial suspicions and circumstantial evidence suggesting snakebite involvement, the autopsies revealed surprising causes of death. The article discusses challenges in accurately attributing deaths to snakebites, and the potential for false claims, and underscores the crucial role of Forensic pathologists in dispelling enigmas. Forensic pathologists are urged to maintain an unbiased approach, allowing postmortem findings to guide conclusions amidst deliberate attempts to mislead. The cases described highlight that ruling out snake bites in cases with positive history is as challenging as opining a case of neurotoxic snake bite as they are mainly the diagnosis of exclusion in autopsy.

Vaginal fluid analysis plays a crucial role in sexual assault investigations. However, vaginal fluid found at crime scenes is usually subject to a certain duration of exposure. This study thus aimed to assess the influence of different durations of exposure to indoor environment on the vaginal microbiota. The 16S rDNA high-throughput sequencing was used on vaginal fluid samples exposed for short-term (30 days) and long-term (240 days), respectively. Despite potential contamination from environmental microorganisms, particularly following long-term exposure, the results indicated that the vaginal microbiota after exposure was still dominated by Lactobacillus. Both in short-term and long-term exposure involving vaginal fluid, there were clusters with time-dependent characteristics, wherein the relative abundances of associated microbial genera showed a trend of increasing or decreasing over time. In addition, each bodily fluid presented with a unique array of dominant bacterial genera, enabling the differentiation of exposed vaginal fluid samples from other bodily fluids (semen, skin, saliva, feces) with a remarkable 98.75 % accuracy rate. Furthermore, the mean absolute error achieved by the long-term deposition time prediction model was 13.54 days. The mean absolute error for the short-term deposition time prediction model was notably lower, reaching just 2.05 days. In summary, this study investigates the variations in microbial communities within vaginal fluid subjected to different indoor exposure durations and explores their potential in body fluid identification and estimating the time since deposition, thereby contributing valuable supporting evidence in forensic investigations.