Forensic science international最新文献

Sexual assault cases typically involve intense physical contact between victim and perpetrator, resulting in a high chance of trace transfer. In addition the victim’s, and sometimes the suspect’s, declaration is available, and can help direct the forensic investigation. However, many cases are still closed because of insufficient proof or an unknown perpetrator.Previously in Belgium, the forensic analysis strategy was often limited to the detection of human sperm fluid and if not found, the forensic part of the case was closed.Therefore, the Forensic Advice service from the Belgian National Institute for Criminalistics and Criminology (NICC) together with the public prosecutor’s office of the Judicial district Antwerp, department Antwerp started “Project code 37”. In Belgium every type of crime receives a code and sexual assault cases are categorized under code 37. Because a forensic advisor focuses on the potential of forensic examination on physical objects, the project focused on cases with samples taken on the victim or clothing available.The goal of the project was to perform a contextual analysis in order to go beyond the standard sperm fluid-orientated approach and evaluate if this had a positive impact on the conviction rate. The project also aimed to evaluate the impact of the consistent use of toxicological analyses on conviction rates. Through this systematic contextual analysis, it became clear that four clear categories could be defined: (1) cases with an unknown perpetrator, (2) cases where the suspect denies all contact, (3) cases where the suspect denies (part of) the sexual contact, and (4) cases where only the consent of the victim is disputed. These categories all assumed one female victim and one male perpetrator. Together with the NICC’s DNA, trace evidence and toxicology lab, an analysis strategy was drafted for the four categories. All cases that do not fit this description were gathered in a fifth category (custom-made cases), as the victim’s/perpetrator’s sex has a significant effect on the forensic analysis strategy. At the end of the project, a comparison was made with the same set of cases from another judicial year where the standard analysis strategy was used. For all the categories for which data was available, there was a rise of the conviction rate and a decrease in the number of dismissed cases.

The pars basilaris forms a central component of the immature basicranium and owing to its resilience to post-mortem and taphonomic changes, holds significance across evolutionary, clinical, and forensic contexts. While size and shape parameters of the pars basilaris have been investigated, little is known about the influence of the underlying bone mineral density on the morphometry of this bone during growth. This study aimed to investigate the development and growth of the pars basilaris with specific reference to changes in bone density patterning and development of osteological features, during the prenatal and early postnatal periods of life. A total of 109 pars basilari were sourced from the Johannesburg Forensic Paediatric Collection, University of the Witwatersrand, South Africa. The study sample was subdivided into early prenatal (<30 gestational weeks), prenatal (30–40 gestational weeks) and postnatal (birth to 7.5 months) groups and micro-CT scanned to assess bone mineral density patterns across seven regions of interest. Size and shape changes were analysed using 11 digitized landmarks and geometric morphometrics. When comparing across age groups, the assessed dimensions increased with growth manifesting as a deepening at the anterior border of the foramen magnum, development of the lateral angles and widening of the bone at the lateral projections and spheno-occipital synchondrosis. However, no significant changes in the distribution of bone mineral density were observed. An appreciation of morphological changes and bone quality at specific growth sites in the pars basilaris is essential when analyzing remains of unknown provenance for the purposes of identification in disaster victim settings.

According to the Sydney Declaration, “Forensic science is [… an] endeavour to study traces […] through their detection, recognition, recovery, examination and interpretation to understand anomalous events of public interest (e.g., crimes, security incidents).” This science is focused on establishing the nature and relationships among entities related to events having a potential legal impact. Entities can be (groups of) persons, objects, activities and their corresponding sources, events and traces. Although uniqueness of an entity has been traditionally accepted as a principle of forensic science, this paper argues and illustrates that such uniqueness is illusory: Not only can an entity evolve spatially and temporally, but at any specific instant, it differs from itself according to the level of precision at which it is considered. Its characteristics vary based on when, how and by whom it is perceived. We introduce the concept of fuzzy entities - defined to formally include some essential uncertainty or imprecision. The essential impreciseness and subjectivity of an entity gives a new perspective that allows us to revisit Kirk's principle of individuality and to propose to replace it with a new principle of fuzzy unicity. We believe that this new perspective has the potential to strengthen forensic science foundations and bring closer its disciplines, which is an important step towards a harmonized forensic science.

Determining the biological source of a stain can be important information for both investigators and the judiciary in criminal cases. Immunochromatographic assays are commonly used in forensic science for the identification of human biological material. It has previously been demonstrated that various environmental, thermal and chemical insults can affect the efficacy of ABAcard® HemaTrace® in the detection of human blood. In this study, the efficacy of three tests – ABAcard® HemaTrace®, ABAcard® p30, and RSID™-Saliva – was determined for the detection of blood, semen, and saliva respectively, after the fluids had been exposed to adverse environmental conditions. Each biological fluid was deposited on cotton swatches and exposed to infrared (IR) light using a 100 W heat lamp emitting IR light between 620 and 750 nm and heat of 32° for 24, 36 and 48 h. Cotton swatches bearing biological fluids were also buried in outdoor soil for 3, 4 and 5 weeks. To test common forensic scenarios where biological material may be exposed to solar light, samples were placed on a car bonnet and left for 24, 36 and 48 h. ABAcard® HemaTrace® was able to detect haemoglobin in blood that had been exposed to IR and solar light up to 48 h. False negative ABAcard® HemaTrace® results were obtained from 60 % of blood samples buried for 3 and 4 weeks, and 80 % of blood samples buried for 5 weeks. ABAcard® p30 was able to detect p30 in semen that had been exposed to IR and solar light up to 48 h, except for one false negative after 48 h of IR exposure. False negative ABAcard® p30 results were obtained from all semen samples buried for 3, 4 and 5 weeks. RSID™-Saliva was able to detect α-amylase in saliva in all instances, with no false negative results observed. The findings from this study highlight the need to consider the context in which human blood, semen and saliva are found when reporting on negative immunoassay results.

In the forensic science context petrol is considered the most common fire accelerant. However, the identification and classification of petrol sources through the years has been proven to be a challenge in the investigation of fire related incidents. This research explored the possibility of identification and classification of petrol sources using high field NMR spectroscopy. In this study, ¹H NMR profiling, using specific pulse sequences to analyse neat aliquot petrol samples of different brands collected at different times across the UK and Ireland is shown, for the first time, to provide a diagnostic ‘fingerprint’ with specific chemical compounds that can be used for identification and classification of petrol samples. This enables linkage of unknown petrol samples to a source and in addition provides a tool which allows exclusion of potential petrol sources. A new, innovative method using ¹H selTOCSY is described for the individualization and classification of petrol samples through the identification of olefinic markers in the samples. Those markers were identified as (i) 3-methyl-1-butene, (ii) a mixture of 1-pentene and 3-methyl-1-butene, (iii) 2-methyl-2-butene and (iv) a mixture of cis and trans-2-pentene.

Introduction

It is crucial for dental surgeons to use the mechanical properties of dental prosthetic materials to correlate the submersion time in a mangrove environment.

Objective

This study aimed to submerge dental prosthetic materials, such as acrylic resin and zirconia, contained within acrylic resin disks in a mangrove environment, and analyze the alterations in mechanical parameters, such as surface roughness and microhardness, to estimate submergence time in similar forensic situations.

Materials and methods

A total of 6 specimens was embedded in acrylic resin disks numbered from 1 to 6. The materials were polished for initial parameter readings a day before submersion, and new readings were obtained 1after submersion. All specimens were subjected to surface roughness analysis, in addition to Knoop microhardness analysis for acrylic resin and Vickers microhardness analysis for zirconia. After the experiment, the data were computed for statistical comparation of the materials properties different parameters.

Results

There was a significant increase in surface roughness and Knoop microhardness was reduced in the Acrylic Resin samples (p< 0.05); however, no statistically significant differences were observed in the roughness or Vickers microhardness values of the zirconia samples.

Conclusion

Zirconia prosthetics were more resistant to degradation when submerged in a mangrove environment compared to acrylic resin ones; however, owing to the obstacles inherent in this study, we suggest further research on the properties of prosthetic materials submerged in mangroves or other environments, which could bolster the work of dental professionals in forensic medical institutes.

Mass disaster events can result in high levels of casualties that need to be identified. Whilst disaster victim identification (DVI) relies on primary identifiers of DNA, fingerprints, and dental, these require ante-mortem data that may not exist or be easily obtainable. Facial recognition technology may be able to assist. Automated facial recognition has advanced considerably and access to ante-mortem facial images are readily available. Facial recognition could therefore be used to expedite the DVI process by narrowing down leads before primary identifiers are made available. This research explores the feasibility of using automated facial recognition technology to support DVI. We evaluated the performance of a commercial-off-the-self facial recognition algorithm on post-mortem images (representing images taken after a mass disaster) against ante-mortem images (representing a database that may exist within agencies who hold face databases for identity documents (such as passports or driver's licenses). We explored facial recognition performance for different operational scenarios, with different levels of face image quality, and by cause of death. Our research is the largest facial recognition evaluation of post-mortem and ante-mortem images to date. We demonstrated that facial recognition technology would be valuable for DVI and that the performance varies by image quality and cause of death. We provide recommendations for future research.

Gel blasters are currently imported and marketed as children’s toys in Australia. Gel blasters closely imitate the appearance of many genuine firearms of all types and are designed to propel small hydrated gel balls of approximately 7–8 mm in diameter, by means of compressed air or gas. They are considered illegal in all states of Australia except Queensland but these items aren’t specifically written into most state firearms legislation. However, to be considered as children’s toys, they must not exceed the recommended kinetic energy (KE) of 2500 J/m² as outlined in the Australian/New Zealand Standard Safety of Toys – Part 1: Safety aspects related to mechanical and physical properties (Safety of Toys ASNZS ISO 8124.1:2019) [1]. The aim of this study was to determine if a range of gel blasters would conform to the Australian & New Zealand Standard and have projectiles with kinetic energy of less than 2500 J/m². Utilising the testing procedure outlined in ASNZS ISO 8124.1:2019 (Australian/New Zealand Standard Safety of Toys – Part 1: Safety Aspects related to Mechanical and Physical Properties (Safety of Toys ASNZS ISO 8124.1:2019) [1]), a range of gel blasters were tested. In addition, a number of NERF™ toys and airsoft firearms were tested to provide reference between an accepted child’s toy and items considered to be a firearm, such as airsoft firearms. A NERF™ toy (commonly referred to as a blaster) fires a foam projectile at very low velocities through direct spring/striker impact to the rear of the dart, battery-powered motorised flywheel, or by compressed air generated by a small piston inside a cylinder. Airsoft firearms are designed to fire hard plastic balls (typically 6 mm in diameter) and can achieve velocities upwards of 90 m/s with the potential to cause injuries to soft tissue. Results showed the KE per unit area of pellets fired from airsoft firearms significantly exceeded the recommended 2500 J/m² ranging from approximately 10,620 J/m² to 69,650 J/m². Twenty of the twenty-four gel blasters tested (83 %) exceeded 2500 J/m², with values ranging between 2112 J/m² and 42,645 J/m². NERF™ toys were found to be notably under 2500 J/m², ranging from approximately 1230 J/m² to 2129 J/m². The results suggest that the majority of gel blasters (items of seizures) tested, currently being imported and marketed as children’s toys in Australia, easily exceed 2500 J/m² as outlined in the ASNZS ISO 8124.1:2019 and are not safe to be marketed and sold as children’s toys. Reinforcing the position of most jurisdictions, the Australian Federal Police (AFP) in Canberra made the following statement in 2019: ‘ACT (Australian Capital Territory) Policing is reminding the public that replica firearms known as gel blasters are illegal in the ACT’. Taking the results determined throughout this research an