Forensic science international最新文献

The efficient and accurate analysis of illicit drugs remains a constant challenge in Australia given the high volume of drugs trafficked into and around the country. Portable drug testing technologies facilitate the decentralisation of the forensic laboratory and enable analytical data to be acted upon more efficiently. Near-infrared (NIR) spectroscopy combined with chemometric modelling (machine learning algorithms) has been highlighted as a portable drug testing technology that is rapid and accurate. However, its effectiveness depends upon a database of chemically relevant specimens that are representative of the market. There are chemical differences between drugs in different countries that need to be incorporated into the database to ensure accurate chemometric model prediction. This study aimed to optimise and assess the implementation of NIR spectroscopy combined with machine learning models to rapidly identify and quantify illicit drugs within an Australian context. The MicroNIR (Viavi Solutions Inc.) was used to scan 608 illicit drug specimens seized by the Australian Federal Police comprising of mainly crystalline methamphetamine hydrochloride (HCl), cocaine HCl, and heroin HCl. A number of other traditional drugs, new psychoactive substances and adulterants were also scanned to assess selectivity. The 3673 NIR scans were compared to the identity and quantification values obtained from a reference laboratory in order to assess the proficiency of the chemometric models. The identification of crystalline methamphetamine HCl, cocaine HCl, and heroin HCl specimens was highly accurate, with accuracy rates of 98.4 %, 97.5 %, and 99.2 %, respectively. The sensitivity of these three drugs was more varied with heroin HCl identification being the least sensitive (methamphetamine = 96.6 %, cocaine = 93.5 % and heroin = 91.3 %). For these three drugs, the NIR technology provided accurate quantification, with 99 % of values falling within the relative uncertainty of ±15 %. The MicroNIR with NIRLAB infrastructure has demonstrated to provide accurate results in real-time with clear operational applications. There is potential to improve informed decision-making, safety, efficiency and effectiveness of frontline and proactive policing within Australia.

Here we present our preliminary studies into the inorganic pigments Han blue (BaCuSi₄O₁₀) and Han purple (BaCuSi₂O₆) as near-infrared luminescent fingerprint dusting powders. These pigments were developed in ancient China around 800 BCE and both show luminescence in the NIR region. There remains, however, ambiguity in the literature concerning their photophysical properties. Samples of Han blue and Han purple artist’s pigments were characterized by optical microscopy, infrared, ultraviolet-visible absorbance and luminescence spectroscopy. Their performance as fingerprint dusting powders, without any further treatment, on non-porous surfaces were compared to exfoliated lipophilic coated Egyptian blue and commercial fluorescent powders in a pilot study. These results demonstrate for the first time that both ancient pigments show promise as alternative dusting powders for latent fingermarks.

Insertion or deletion (InDel), a genetic marker with short insertion/deletion fragment length polymorphism, is widely used in the field of forensic biological research. The Guizhou Shui (Shui) ethnic group and Guizhou Dong (Dong) ethnic group are located in the southwestern region of China, with rich historical and cultural background. In this study, a self-developed panel included 56 ancestry informative marker (AIM)-InDel loci on the autosomes, three InDel loci on the Y chromosome, and one sex-determined Amelogenin locus. Firstly, we used the 56 autosomal loci to assess the forensic individual identification and paternity testing abilities in both the Shui and Dong groups. The cumulative probability of match and probability of exclusion for the Shui and Dong groups were 2.228×10⁻¹⁵ and 0.991518139; 7.604×10⁻¹⁶ and 0.992253273, respectively. In addition, we also conducted in-depth analyses for the genetic backgrounds and structures of the Shui and Dong groups based on 56 AIM-InDel loci. This research has found that the Shui and Dong groups have close genetic relationships with the East Asian populations. Meanwhile, we also found that the Shui group has a close genetic distance with Chinese Dai in Xishuangbanna (CDX). These insights provide vital information for the genetic structures of the Shui and Dong groups, as well as basic population data and molecular biological evidence support for individual identification and biogeographic ancestry inference in forensic genetic field.

This study details trends in direct alcohol biomarker concentrations from civil cases within the United Kingdom (UK). Our subject cohort in this study related to family law litigation, where an individual was subject to an alcohol monitoring order by the court. This monitoring was conducted by quantification of alcohol biomarkers Phosphatidlyethanol (PEth) in dried blood spots (DBS) and Ethyl Glucuronide (EtG) and Ethyl Palmitate (EtPa) from hair segments. In total 298 PEth cases predominantly from the South East of England during the period July 2022 to August 2023 were analysed for alcohol biomarkers in DBS and hair. Subjects alcohol intake was classified as abstinence/low alcohol consumption, moderate or excessive alcohol consumption, based on a combination of Society for Hair Testing and PEth Net guidelines. Our results indicate that 33 % of PEth concentrations were consistent with excessive alcohol use (>200 ng/mL DBS), with 36 % consistent with social or moderate alcohol use (20–200 ng/mL DBS). In relation to EtG and EtPa 23 % and 31 % of subjects were classified as excessive alcohol users respectively. This study indicates that DBS sampling of PEth is a more sensitive predictor of alcohol use, in particular, at differentiating between moderate and excessive alcohol use compared to EtG and EtPa testing in hair. The authors suggest that increased frequency in the sampling of PEth in DBS (multiple occasions per month) may provide a more accurate assessment and simplification of the interpretation criteria of alcohol patterns rather than the combined hair testing and DBS sampling that are typically requested by UK courts.

Cannabis is the most widely consumed illicit drug worldwide. As consumption rates increase, partially due to the decriminalization of its use for medicinal and recreational purposes, analytical methods for monitoring different cannabinoids in several biological matrices have been developed. Herein, a simple and fast extraction procedure to extract natural cannabinoids from oral fluid (OF) samples was developed and fully validated according to the ANSI/ASB 2019 Standard Practices for Method Validation in Forensic Toxicology. Using only 0.2 mL of neat OF, the analytes [Δ⁹-tetrahidrocannabinol (THC), 11-hydroxy-Δ⁹-tetrahydrocannabinol (THC-OH), 11-nor-9-carboxy-Δ⁹-tetrahydrocannabinol (THC-COOH), cannabinol (CBN) and cannabidiol (CBD)] were extracted by protein precipitation with a mixture of methanol:acetonitrile (80:20, v/v); the extracts were centrifuged, evaporated to dryness and reconstituted in 100 µL of methanol. Analysis was performed by liquid chromatography coupled to tandem mass spectrometry (LC–MS/MS). The developed methodology produced linear results for all compounds, with working ranges of 0.1–50 ng/mL for THC, 0.5–50 ng/mL for THC-OH, CBN and CBD, and 0.05–1 ng/mL for THC-COOH. Ion suppression was observed for THC, CBN and CBD, which did not impair sensitivity considering the low limits of quantification (LOQs) and limits of detection (LODs) obtained (which varied between 0.05 and 0.5 ng/mL). The extraction procedure produced great recoveries, and the compounds were stable. No interferences were found, and the method proved to be extremely fast, selective, precise, and accurate for use in routine analysis. The method was successfully applied to authentic samples.

Pepper sprays of the OC type constitute the majority of self-defense sprays available on the market. The active ingredient in these preparations is pepper extract: Oleoresin Capsicum, which contains capsaicinoids - natural compounds with irritant properties. Preparations from OC pepper sprays can be distinguished based on differences in the quantitative ratios of four main capsaicinoids: capsaicin, dihydrocapsaicin, nordihydrocapsaicin, and nonivamide. This raises the question whether information on the quantitative ratios of capsaicinoids can also provide answers to questions regarding comparisons of traces of OC preparations, such as whether traces revealed on the clothing of the victim could originate from an OC spray secured from the suspect, or whether traces on the clothing of the suspect and the victim could come from the same pepper spray. Such comparisons would be viable only if the capsaicinoid profile remained unchanged during evidence storage and as a result of solvent extraction from the tested material. The aim of the presented research was to determine if this is indeed the case. Model aging experiments were conducted to examine whether the capsaicinoid profile in traces of OC preparations changed over time and whether solvent extraction affected this profile. Samples of five different OC preparations were applied to cotton swabs, which, after the evaporation of volatile solvents, were placed in three types of packaging with varying levels of tightness and transparency (tight amber vials, polyethylene bags, paper envelopes). These prepared samples underwent solvent extraction with methanol and analysis using gas chromatography – mass spectrometry, after 28, 84, 147, 196, 252, and 301 days from preparation. The likelihood ratio (LR) was applied as a statistical tool to investigate the data obtained. The LR model was computed using the three variables based on the relative content of nordihydrocapsaicin, nonivamide, and dihydrocapsaicin. The cotton swabs used in the experiments served as a model for both the swabs used by the police for securing liquid evidence and the cotton clothing of individuals sprayed with OC pepper sprays. The findings of the conducted studies suggest that the quantitative relationships of capsaicinoids indeed change over time, both in preparations stored in original containers and in traces of these preparations present on clothing. For traces of OC preparations secured on swabs or present on clothing, these changes are more significant the longer the sample is stored and the less airtight the packaging used.

F-500 Encapsulator Agent (EA) is a fire suppression agent that is an alternative to traditional firefighting foams. It is marketed as having the capability to act on all four parts of the fire tetrahedron as well as being environmentally friendly and non-toxic. An internal survey of the use of F-500 EA by fire departments encountered by the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) ignitable liquid detection canine (ILDC) handlers in 2022 showed that this product is not yet in widespread use across the country, but where it has been implemented, it is frequently utilized on a variety of types of fires. Additional agencies are researching the product to determine if it should be adopted. As this product appears to be growing in popularity, it is important to understand whether the use of the product would affect a canine’s ability to detect ignitable liquids or a forensic laboratory’s ability to identify the presence of an ignitable liquid. Burned wood and burned carpet, two commonly encountered substrates, were spiked with gasoline or a heavy petroleum distillate (HPD) and F-500 EA was applied. At various time intervals, ILDC teams surveyed the samples and laboratory analysis was conducted. Results showed that the presence of F-500 EA can negatively affect canine alerts and the laboratory’s ability to identify ignitable liquids.

This paper highlights how micro-CT was used to assist in the investigation of hybrid firearms constructed using a mixture of plastic and metal components, as a complementary technique to the physical examination performed by firearms experts. In recent years, there has been an increase in the complexity and sophistication of 3D printed and hybrid firearm designs. This was also the case in the investigation presented herein, with the firearms seized demonstrating a step change in the threat level they pose through their complexity. Thus, we describe how data produced from micro-CT scans was used to help firearms experts study the viability and mechanics of two hybrid weapons prior to dismantling and test-firing. This process aided experts in determining whether components were 3D printed or manufactured through other means, whilst ensuring that a digital record (digital twin) was retained in case evidence was damaged during testing. Finally, we show how the data was presented visually through animations and as evidence in court. This proved to be imperative when communicating to the judge, jury, and wider investigating teams, the complex multiple components and mechanisms within the firearms.

Back ground

The sample collection and preservation before transportation to a Forensic Science Laboratory in a medicolegal case in India is a crucial step in establishing a link between accused, victim, crime scene and the weapon. This paper discusses pioneering advancement in health technology—a state-of-the-art sample dryer developed to preserve biological samples during Forensic investigations. This unique design has been officially registered with the design office in India as a copy right.

Aims and Objectives

The primary goal of the sample dryer is to augment the preservation of biological evidence by removing moisture content through air drying before packaging, sealing and its transportation to a Forensic Science Laboratory.

Material and Methods

The process of air drying of biological samples by variety of experiments conducted in sample’s dryer designed for the purpose which employs a range of air movement techniques including horizontal, vertical, and circular laminar flows to swiftly extract moisture from the samples. The drying duration for each experimental sample was documented upon manual confirmation of complete drying.

Results

The results were extraordinary, showcasing that the sample’s dryer reduced the drying time drastically by up to 27 times lesser in comparison to conventional methods for identical samples. The diverse airflow patterns generated by the sample dryer unequivocally demonstrated it’s utility in achieving superior sample preservation through efficient air drying.

Conclusion

Given the exceptional outcomes observed in the experimental phase, the authors strongly advocate for the widespread adoption of this innovative sample’s dryer equipment to ensure effective air drying of biological samples and their efficient sample preservation to enable successful forensic analysis as expected.

Given that microbiological analysis can be an alternative method that overcomes the shortcomings of traditional forensic technology, and skin samples may be the most common source of cases, the analysis of skin microbiome was investigated in this study. High-throughput sequencing targeting the V3-V4 region of 16S rRNA gene was performed to reveal the skin microbiome of healthy individuals in Guangdong Han. The bacterial diversity of the palm, navel, groin and plantar of the same individual was analyzed. The overall classification based on 16S rRNA gene amplicons revealed that the microbial composition of skin samples from different anatomical parts was different, and the dominant bacterial genus of the navel, plantar, groin and palm skin were dominated by Cutibacterium, Staphylococcus, Corynebacterium and Staphylococcus, respectively. PCoA analysis showed that the skin at these four anatomical locations could only be grouped into three clusters. A predictive model based on random forest algorithm showed the potential to accurately distinguish these four anatomical locations, which indicated that specific bacteria with low abundance were the key taxa. In addition, the skin microbiome in this study is significantly different from the dominant microbiome in saliva and vaginal secretions identified in our previous study, and can be distinguished from these two tissue fluids. In conclusion, the present findings on the community and microbial structure details of the human skin may reveal its potential application value in assessing the location of skin samples and the type of body fluids in forensic medicine.