Forensic Sciences Research最新文献

[This corrects the article DOI: 10.1080/20961790.2018.1479148.].

Bullet ricochets often leave impact sites that can be useful for shooting incident reconstruction. Here, we assess the proposal that these sites can potentially provide information about the design and composition of the projectile and possibly the corresponding firearm. We produced impact sites in concrete from five bullet types fired at two distances, for a total of 10 experimental conditions. Then, using elliptical Fourier analysis, we assessed the 297 bullet ricochet impact sites' plan-view outline shapes. Of the different bullet types, the 45 calibre Hollow Points exhibited the greatest variability in ricochet impact site shape, and the greatest potential for diagnosis. Overall, statistical assessment of robust sample sizes of ricochet impact sites suggests that there is too much overlap between different bullets' ricochet sites' plan-view form for confident identification of bullet design and composition, much less identification of the firearm from which it originated. We conclude with an extended discussion about future experiments involving bullet ricochet impact sites, including the employment of "paradigmatic classification", which can both organise the testing of experimental variables as well as illustrate the tremendous amount of experimental work that still needs to be conducted before researchers or firearm examiners draw firm conclusions. Key PointsBullet ricochet impact sites often occur in shooting incidents.We analysed bullet richochet impact site shapes in concrete using elliptical Fourier analysis.Results suggest different bullet types' ricochet impact shape morphospaces overlap with each other.This overlap obscures conclusions about the design and composition of the projectile and possibly the responsible firearm.

The ability to develop latent fingermarks from fired and unfired cartridge cases can be crucial in resolving crime cases and advancing forensic investigations. Currently, there is a lack of consensus on the ideal technique to employ for the enhancement of latent fingermarks from fired and unfired cartridge cases. This review therefore aims to explore techniques and methods employed to develop latent fingermarks from fired and unfired cartridge cases. A systematic search of peer-reviewed original articles was performed from four main electronic databases: ScienceDirect, Scopus, Google Scholar, and PubMed. According to data from our review, the most well-established method for developing latent fingermarks from fired and unfired cartridge cases remains the sequential application of cyanoacrylate fuming, followed by gun bluing, and the application of a fluorescent dye called basic yellow 40. This review also discusses the current scope of research, highlights the limitations, and provides practical recommendations for future perspectives. Key points  Fingermark evidence on fired and unfired cartridge cases cannot be undervalued.The enhancement of latent fingermarks from fired cartridge cases is possible although challenging.Enhancement of latent fingermarks from fired cartridge case is possible with cyanoacrylate fuming followed by gun bluing and basic yellow 40.Recover Latent Fingerprint Technology, palladium deposition, and cold patination fluid are promising fingermark enhancement techniques.

The detection and identification of chemical warfare agents (CWAs) present challenges in emergency response scenarios and for safety and security applications. This study presents the development and validation of an innovative analytical method using a gas chromatography (GC) and quartz-enhanced photoacoustic spectroscopy (QEPAS) sensor for the detection of stimulants for six CWAs. Following the guidelines of the European Network of Forensic Science Institute (ENFSI) and the Commission Implementing Regulation (EU) 2021/808, the analytical method was validated. The validation results demonstrated the robustness and reliability of both the GC and QEPAS modules. Moreover, with regard to the toxicological threshold levels, this study highlights the efficacy of a prototype of a portable device for real security and safety applications. Furthermore, a machine learning (ML) approach was developed to automate the detection and identification of CWAs' stimulants. The workflow involved two interconnected stages: detection based on chromatographic retention times (RTs), and identification using infrared (IR) spectra through the one-class support vector machines classifier. The classifier was activated only after obtaining a positive detection based on RTs. The results highlight the ML model's effectiveness in CWA detection and identification, combining RT analysis and IR spectrum classification, achieving 97% accuracy at a 95.5% confidence interval and 99% accuracy at a 99.7% confidence interval; this result demonstrates the model's utility for real-world security and safety applications for CWAs.

Age estimation is a critical aspect of forensic entomology, especially in the examination of pupae. The use of proteins as a means for age identification shows great promise. In this study, proteomic techniques were employed to investigate differentially expressed proteins (DEPs) during the intrapuparial stage of Chrysomya megacephala. Specimens were sampled at four distinct time points: 0 h (Group A), 24 h (Group B), 48 h (Group C), and 72 h (Group D). Our analysis uncovered 56 DEPs between Groups B and A, 116 DEPs between Groups C and A, and a total of 152 DEPs between Groups D and A. These DEPs were categorized into nine clusters based on their expression patterns. Cluster 1 exhibited an increasing trend in protein expression, while Cluster 4 displayed the opposite pattern. Clusters 2, 6, and 9 showed an initial rise followed by a decline, whereas Cluster 3 demonstrated the reverse trend. Cluster 8 indicated an initial rise, a subsequent drop, and another rise, while Cluster 7 showed an initial decrease, followed by an increase and a minor decrease. Notably, the C-type lectin domain-containing (CTLD) protein and Failed axon connections (Fax) protein consistently displayed an upward trend. These two DEPs were selected for validation using the parallel reaction monitoring technique-targeted proteomics, confirming the trends observed in the initial analysis. In summary, this study highlights the potential of using proteins as reliable biomarkers for estimating pupal age.

The characteristics of commercially available thermochromic ink pens have been studied and described since their appearance in 2006. The wide variety of brands and models now available warrants further study using an expanded sample size, to differentiate the general characteristics from specific characteristics. Herein, the ink strokes of 15 pens purchased in the province of Córdoba, Argentina were studied. First, the initial unaltered strokes were examined. Second, heat-manipulated strokes (with and without friction) were evaluated. Several characterization techniques were employed, such as observation by the naked eye, optical magnification, and light irradiation using different spectral bands. In 100% of the unaltered strokes, the general characteristics of thermochromic inks, such as ink accumulation at the end of the stroke path and a "pasty appearance", were found. It was possible to visualize colourless strokes (i.e. erased strokes) based on their contrast with the paper by shining oblique light at an opposite angle to that of the observation. In addition, the responses to ultraviolet (UV) (365 and 254 nm) and cyan light (505 nm) by infrared techniques were useful for distinguishing the thermochromic ink. Specific characteristics, such as high relief in areas of ink accumulation, less ink accumulation in the internal zone of the stroke, and intensity differences in infrared radiation (IR) luminescence emitted by different brands and models, could be useful in determining the writing tool that was used.

Key points: Thermochromic ink disappears with heat but is reversible with cold.UV techniques and IR photography serve to make thermochromic ink visible.Initially use oblique white light opposite to the angle of observation to make strokes visible.

Currently, forensic death investigations in the Western Cape, South Africa do not account for vertebrate scavenging activity; however, previous research in the city of Cape Town has shown a significant impact on the rate of decomposition due to scavenging by the local Cape grey mongoose (Galerella pulverulenta). This pilot study aimed to develop a framework to more robustly quantifiably describe and analyse the scavenging behaviour of this species on a single clothed 60 kg porcine carcass in a forensically significant location in Cape Town (i.e., a region of the city with a proportionately large forensic case load). Feeding behaviours are the focus of this framework and analysis, but non-feeding behaviours in the immediate vicinity of the carcass are also distinguished and described. Additionally, it was assessed whether all behaviours varied in their frequency of occurrence as decomposition progressed. More than 40 h of mongoose interaction with the carcass were recorded using motion-activated infrared-capable wildlife trail camera videography. The highest frequencies of scavenging activity were observed in the abdominal and the eye socket regions of the carcass. Abdominal feeding largely involved soft tissue modification, whereas more intensive activity in the eye socket suggested a higher likelihood of hard tissue scavenger artefacts being found there. A Kruskal-Wallis test confirmed that some feeding behaviours occur more frequently during specific decomposition stages. For example, scratching is common during the earlier stages of decomposition, ostensibly to create an opening in the flesh. Twisting whilst biting was only observed in latter stages of decomposition, likely due to the increased toughness of the soft tissue as it desiccated. This pilot research offers detailed insight into scavenger behaviours previously unreported in the forensic taphonomic literature, and proposes a provisional method of quantifiable analyses of scavenger behaviours that extends what has previously been published in the forensic taphonomic literature. Local validation of the observations is planned, and international replication of the research for diverse scavenger guilds is encouraged.

Key points: Novel framework for detailed quantitative analysis of vertebrate scavenger behavior using the Cape grey mongoose as a model.First systematic study of scavenger behaviour in South Africa and likely Africa-wide.Cape grey mongoose preying on blow fly larvae, emphasizing the necessity of videographic documentation.

DNA transfer, whether intentional or not, is becoming an important part of forensic evidence gathering and analysis. This study seeks to determine the impact of liquid antibacterial soap and hand sanitizer use on the DNA present in the palms of hands that may potentially reduce direct transfer. Twelve volunteers were enrolled and typed. Afterwards, each palm was swabbed without considering previous activities to collect background DNA profiles. Subsequently, each subject washed his/her hands for 30 s with antibacterial soap first, and after with sanitizing gel and then air-dried them; after drying, each palm was immediately swabbed for DNA typing. The results of this study demonstrated that the possibility of recovering a complete profile from a hand swab is strictly related to previous activity: considering the results of the samples taken before handwashing, there is the possibility of having a median recovery of 80.01%, while it is very low (median recovery was 3.43%) after hand washing with antibacterial soap followed by alcohol-based hand sanitizer. Analyzing the results after handwashing, we were unable to detect any drop-in alleles. Moreover, we determined that in 11/12 samples, less than nine alleles were detected: considering that the kit used for the profiling could analyze 23 short tandem repeats (STRs), it is possible to conclude that we obtained inconclusive profiles. Based on the findings of the present study, it is more difficult to obtain a perpetrator's profile if he/she used liquid antibacterial soap and hand sanitizer immediately before the criminal action.