Forensic Examination Research Articles

Accuracy and Reproducibility of Bullet Comparison Decisions by Forensic Examiners

Few previous studies have assessed the accuracy and reproducibility of bullet comparison decisions by firearms examiners, and none have evaluated accuracy of examiners’ decisions when comparing damaged bullets, comparisons of questioned bullets, or the effects on decision rates of using jacketed hollow-point vs. full metal jacket bullets. In this study, 49 practicing forensic firearms examiners conducted 3,156 comparisons of bullets, including bullets ranging in quality, bullets from different types of ammunition, and bullets fired from various makes/models of firearms. The study evaluated two scenarios commonly used in casework: questioned-questioned (QQ) comparisons of two bullets from unknown sources, and known-questioned (KQ) comparisons in which a bullet from an unknown source is compared to three known exemplars from a single firearm. Key findings: after controlling for other factors, QQ vs. KQ comparisons had relatively limited effects on decision rates; rates of inconclusive responses were inversely related to bullet quality; bullets fired from polygonally-rifled pistols resulted in more inconclusive or unsuitable responses than conventional rifling; on nonmated comparison sets, the rate of (true) exclusions was particularly high when comparing different caliber bullets, and was higher on comparisons of different makes/models of firearms vs. the same model of firearm; comparisons in which different types of ammunition were fired from the same firearm had a high rate of erroneous exclusions; decision rates differed notably by firearm model; decision rates varied notably among the participants. Because the measured rates vary dramatically due to these various factors, we recommend against using overall decision rates to summarize the results of this study. Significance StatementComparisons of bullets by forensic firearms examiners are a critical part of the criminal justice system, seeking to determine whether recovered bullets from crime scenes can be attributed to specific firearms. This paper reports the results of a research study designed to assess the accuracy and reliability of forensic bullet comparison decisions, which is important to assess scientific validity for admissibility in court. Few studies have been conducted assessing the accuracy of forensic bullet comparison decisions, and no previous studies have evaluated the accuracy and reproducibility of decisions made by practicing forensic firearms examiners when comparing bullets of varying quality or bullets of different types, or when making comparisons of questioned bullets.

Forensic footwear examination: A systematic review of the existing literature

Forensic footwear examination: A systematic review of the existing literature

The mouse gingiva and HIF-1α, a key gene of hypoxic environment, as tools for post-mortem time estimation.

The post-mortem interval (PMI) is the time elapsed between the death of an individual and its forensic examination. It is a crucial information for judicial authorities, but current techniques still cannot establish a precise time interval. Novel approaches are therefore required. Recently, gingival tissue has emerged as interesting for forensic analysis thanks to the protection offered by lips to this tissue, limiting the influence of environmental factors. It is also easily accessible, and its sampling is minimally invasive even in the presence of rigor mortis. Moreover, the expression of HIF-1α, a master mediator of the hypoxic environment, has been described in gingival samples at different post-mortem (PM) times. We have hypothesized that the time-dependent post-mortem expression of HIF-1α could serve as a biomarker to more accurately predict the PMI. Our analyses were performed in an animal model, the mouse, where environment can be precisely controlled. Therewith, gingival tissue morphology was evaluated through histochemical staining and HIF-1α expression was analyzed by qPCR, western blots and immunofluorescence at different post-mortem times (0h to 100h). Our results showed (a) a global post-mortem stability of gingival tissue (b) a rapid increase in HIF-1α mRNA expression in the short post-mortem times followed by a slow decrease in transcript expression until 100h PM (c) an expression of the HIF- 1α protein and its degradation products, that follows the mRNA pattern (d) the presence of HIF-1α protein in the epithelial and connective layers of the tissue, with signal accumulation in both gingival strata until at least 32h post-mortem. This pilot study thus validated the mouse and the gingival tissue as models for post-mortem analyses, as well as for studying the fate of proteins such as HIF-1α. Transferring these approaches to human subjects may provide a more accurate estimate of PMI.

Aggressive driving behavior: road rage incidents in Athens from the clinical forensic point of view

Abstract Background Aggressive driving behavior may lead to interpersonal violence. The Athens Metropolitan area has over four million inhabitants. Public transportation has improved over the last decades, mainly due to the work performed before the 2004 Olympic Games but is still lacking in the coverage of the Attica region with fixed track transportation. Thus, traffic in Athens is usually heavy during the day, a fact that combined with limited parking spaces available, acts as fuel to aggressive driving behaviors. For this retrospective study, data from forensic clinical examinations performed at our department by the authors were reviewed. More specifically, cases examined from January 1st, 2012, to September 30rd, 2021, all concerning allegations for road rage were included, totally 177 cases. The data obtained was analyzed by utilizing SPSS Statistics. Results Most victims and perpetrators were drivers of their vehicles. In most cases (85.3%), perpetrators acted alone. 80.2% of victims reported that the incident was triggered by a minor conflict. Perpetrators used mostly just their hands and feet, or even their head as a blunt force instrument to inflict injuries (72.3%). Hammers, crowbars, and brass knuckles were used in 12.4% of cases, while in 9.6% the vehicle was used to overrun the victim. In 2.8% of cases, perpetrators attempted to strangulate the victims, while in 1.7% they used a sharp force instrument. In 9.6% of cases, victims did not sustain any visible external injury. 18.1% of victims sustained just a single injury, while in 72.3% multiple injuries were observed. 69.5% victims sustained merely external injuries, while in 20.2% at least one internal organ injury was sustained. The predominant injury site was by far the head-neck region. In more than one third of the road rage incidents, the injuries could be characterized as grievous. Conclusions Most people involved were male motorists. Females are rarely victims of road traffic violence, and even more rarely act as perpetrators. Commonest injury site was the head-neck region, with second commonest the upper extremities.

Dynamic signatures: a mathematical approach to analysis

Abstract This study evaluates mathematical tools (principal component analysis, dynamic time warping, and the Kolmogorov–Smirnov hypothesis test) to analyse global and local data from dynamic signatures to reduce subjectivity and increase the reproducibility of handwriting examination using a two-step approach. A data set composed of 1800 genuine signature samples, 870 simulated signatures, and 60 disguises (30 formally similar or ‘autosimulated’ and 30 random but different from usual) provided by 30 volunteers was collected. The first step involved global data analysis using principal component analysis and a hypothesis test performed for 62 global characteristics, and associations of these characteristics were analysed through calculations of multivariate distance followed by a hypothesis test. The second step involved the analysis of local characteristics including vertical and horizontal positions, speed, pressure gradient, acceleration, and jerk point-to-point, by using dynamic time warping followed by a hypothesis test. Optimization of sensitivity and specificity metrics of the hypothesis test was explored by varying its stringency and observing accuracy rates for the simulated and genuine groups. A P-value threshold of 1 × 10−10 was found to be optimal, making the test more restrictive and yielding accuracy rates of 96.7% for genuine global data and 88.9% for simulated data. The same cutoff value for local characteristics provided an average accuracy rate of 95.4% for genuine samples and 94.7% for simulated samples, demonstrating high accuracy for both simulated and genuine samples. However, the method did not offer reasonable accuracy rates for disguises, consistent with observations in traditional handwriting examination. Our approach provided satisfactory results for forensic examination use. The visualization of graphs and signatures and analysis of all identifying elements of handwriting by the examining expert are still essential. In future studies, we plan to perform blind tests to validate our approach and propose a rigorous methodology.

ESTIMATION OF FORMANT INFORMATION USING AUTOCORRELATION FUNCTION OF VOICE SIGNAL

Context. The current scientific problem of extracting biometric characteristics of a user of a voice authentication system, which can significantly increase its reliability, is considered. There has been performed estimation of formant information from the voice signal, which is a part of the user template in the voice authentication system and is widely used in the processing of speech signals in other applications, including in the presence of interfering noise components. The work is distinguished by the investigation of a polyharmonic signal. Objective. The purpose of the work is to develop procedures for generating formant information based on the results of calculating the autocorrelation function of the analyzed fragment of the voice signal and their subsequent spectral analysis. Method. The procedures for generating formant information in the process of digital processing of voice signal are proposed. Initially, the autocorrelation function of the analyzed fragment of the voice signal is calculated. Based on the results of the autocorrelation function estimation, the amplitude-frequency spectrum is calculated, from which the formant information is extracted, for example, by means of threshold processing. When the signal-to-noise ratio of the analyzed voice signal fragment is low, it is advisable to iteratively calculate the autocorrelation function. The latter allows increasing the signal-to-noise ratio and the efficiency of formant information extraction. However, each subsequent iteration of the autocorrelation function calculation is associated with an increase in the required computational resource. The latter is conditioned by the doubling of the amount of processed data at each iteration. Results. The developed procedures for generating formant information were investigated both in the processing of model and experimental voice signals. The model signals had a low signal-to-noise ratio. The proposed procedures allow to determine more precisely the width of the spectrum of extracted formant frequencies, significantly increase the number of extracted formants, including cases at low signal-to-noise ratio. Conclusions. The conducted model experiments have confirmed the performance and reliability of the proposed procedures for extracting formant information both in the processing of model and experimental voice signals. The results of the research allow to recommend their use in practice for solving problems of voice authentication, speaker differentiation, speech and gender recognition, intelligence, counterintelligence, forensics and forensic examination, medicine (diseases of the speech tract and hearing). Prospects for further research may include the creation of procedures for evaluating formant information based on phase data of the processed voice signal.

Clinical precision of Aoralscan 3 and Emerald S on the palatal and dentition areas: evaluation for forensic applications

ObjectivesTo compare the precision (repeatability and intermediate precision) of palatal and dentition scans taken with two different intraoral scanners. MethodsThe maxillary arch of 23 individuals was scanned three times using the Aoralscan 3 (Shining 3D) and Emerald S (Planmeca), resulting in 6 scans per individual. The scans were segmented in Meshmixer into palatal and dentition areas. Each replicate of an individual was compared within the specific scanner (repeatability) and to the corresponding replicate of the other scanner (intermediate precision). The scans were aligned using the iterative closest-point algorithm in the Zeiss Inspect software. The mean absolute distance between the aligned surfaces was calculated. Statistical comparisons were made using Friedman's two-way analysis of variance. Data are presented in median (quartile 1; quartile 3) form. ResultsNo significant difference in repeatability was found between Emerald S and Aoralscan 3 for the palate (26 µm [22,26] vs. 22 µm [18,26]) and for dentition (37 µm [31,44] vs. 38 µm [35,48]. Intermediate precision of the palate (32 µm [26,43]) and dentition (72 µm [63; 80]) was significantly lower than the repeatability of Emerald S (p < 0.05, p < 0.001) and of Aorlascan 3 (p < 0.001, p < 0.001). Both precision types of both scanners were significantly lower for the dentition than for the palate (p < 0.001). ConclusionThe precision of the dentition scan is lower than that of the palate. The precision of the Aoralscan 3 is similar to that of the Emerald S scanner. Clinical significanceNovel intraoral scanners could be used with high precision for palatal soft tissue scans, expanding their clinical utility. Aligning scans from two different IOSs still has high precision, facilitating the interchangeable use of intraoral scanners for orthodontic, prosthetic, and forensic examinations.

Improving forensic examiner decision-making through deliberate practice.

Forensic examiners make important decisions to address legal questions, yet there is now ample evidence that their decisions can be subjective and inconsistent. This commentary suggests that elements of deliberate practice may help in not only having more consistent forensic decisions but also toward expected accuracy. Specifically, four elements of deliberate practice: (1) setting a goal, (2) motivation, (3) feedback, and (4) repetition are outlined with examples for addressing issues of cognitive bias and managing stress at work. If any of these elements are missing, such as delayed or no feedback, then suboptimal or no improvement of examiners' decision-making may result. This tool for deliberately improving decision-making may be applicable to other legal professionals; thus, potentially driving policies that may help enhance the criminal justice system broadly.

Ethical Issues in the Forensic Psychiatric Examination of Competency for Execution

Ethical Issues in the Forensic Psychiatric Examination of Competency for Execution

Clarification to “Ethical considerations for demands for evidence in forensic examinations” by Frederick et al. (2024).

Clarification to “Ethical considerations for demands for evidence in forensic examinations” by Frederick et al. (2024).

Jack of all trades, master of one: domain-specific and domain-general contributions to perceptual expertise in visual comparison

Perceptual expertise is typically domain-specific and rarely generalises beyond an expert’s domain of experience. Forensic feature-comparison examiners outperform the norm in domain-specific visual comparison, but emerging research suggests that they show advantages on other similar tasks outside their domain of expertise. For example, fingerprint examiners not only outperform novices in fingerprint comparison, but also in face comparison. Yet, the extent to which their skills generalise is poorly understood. In this study, we investigated the generalisability of perceptual expertise amongst forensic examiners by comparing their performance to novices and other examiners within and outside their area of expertise. We recruited 85 experts from three forensic disciplines (face, fingerprint, and firearms) and asked them to complete four different visual comparison tasks: faces, fingerprints, firearms, and novel-objects. Examiners displayed domain-specific expertise: they outperformed novices and other examiners within their domain of visual comparison expertise. Yet, some of their skill also generalised: examiners also outperformed novices outside their area of expertise. However, while individual differences in examiners’ performance within their domain of experience were associated with their performance in a novel comparison task, they were not related to their performance on tasks outside their expert domain. These results provide key insight into the domain-specific and domain-general contributions of forensic examiners’ perceptual expertise. Forensic expertise lends some generalisable skill to other visual comparison tasks, but best performance is still seen within examiners’ domain of expertise.

Post Mortem Molecular Biomarkers of Asphyxia: A Literature Review.

Asphyxia is a critical condition characterized by inadequate oxygen supply to the body. Post mortem diagnostics of asphyxia present significant challenges in forensic pathology, particularly when there are equivocal signs during autopsy or uncertain circumstantial data. The identification of biochemical biomarkers that indicate asphyxia has emerged as a promising area of research, as these markers can provide vital insights into the physiological changes occurring at the cellular level during asphyxiation. We performed a review of the scientific literature on the search engines Pubmed and Scopus in order to assess the state of the art on this topic. The aim of this study is to analyze which are the most promising markers and methods in the post mortem diagnosis of asphyxia. The literature review highlighted the great potential that molecular investigations can have in the analysis of this type of death, especially considering that hypoxia determines strong biochemical alterations in response to cellular stress. These changes are marked by specific biochemical alterations, which can be detected through various advanced technologies and methodologies, including mass spectrometry, immunohistochemistry, and metabolomic profiling. The review evidenced a combination of markers that can be used for diagnostic purposes in various cases, including mechanical asphyxia, carbon monoxide (CO) poisoning, perinatal asphyxia, and drowning analysis. However, we highlight that, to date, there are still no standard protocols for forensic biochemistry in asphyxia. By scrutinizing the reliability of identified biomarkers and their potential to reshape forensic investigative practices, this research aims to elucidate the critical role that post mortem biochemical analysis can play in diagnosing asphyxia, ultimately contributing to a more nuanced understanding of death-related scenarios and the development of standardized protocols in forensic examinations.

Economic burden of suicide in Sweden in 2022

Abstract Background Suicide and suicidal behaviors bring massive human, social and economic impacts. Estimates of the cost of suicide can give some guidance as to where research on developing new interventions might be focused to give the greatest potential gain. The aim of the study is to quantify the economic cost of suicide in Sweden in 2022. Methods Incidence of suicide attempts and mortality due to suicide, intentional and undetermined (ICD10 X60-X84 and Y10-Y34) were sourced from the Swedish National Board of Health and Welfare databases for 2022. Cost were estimated from a societal perspective, including costs for inpatient and outpatient care, medication, police and justice activities as well as productivity losses due to early mortality. Results In 2022, a total of 1,569 suicide death were registered in Sweden (1,102 men and 467 women). The incidence rate remains stable during the last ten years, 17 death per 100 000. In total, 18,854 patients (10, 359 women and 8,459 men) were treated in inpatient and outpatient hospital care with suicide-related diagnoses, generated 32,843 days in inpatient care and 11,471 outpatient care visits. Direct costs for suicide death including forensic examination, emergency services, police investigation and property damage were estimated as €6,02 million, while indirect costs for productivity losses totaled €690 million. Direct healthcare costs for suicide related treatment were estimated at €54.3 million. Overall, suicide and suicide attempts cost around €750 million per year to society. Conclusions Estimates of the economic burden of suicide are needed for the Swedish setting, and these amounted to €60.3 million in direct costs and €690 million in indirect costs in 2022. The cost might be underestimated because the societal cost of suicide bereaved persons was not considered. These cost estimates can provide useful inputs to a cost-effectiveness analysis of a specific preventive intervention, and to its subsequent evaluation. Key messages • Economic burden of suicide is substantial for society. • Public health policies aimed at the prevention of suicide should be increased.

Forensic Examinations in Cases of Mistaken Biometric Identification

In connection with innovation of modern biometric technologies in various spheres of life, both at the levels of individuals and of the State, there exists an increasing risk of serious negative consequences of potentially possible mistaken identifications. Such cases already happened both in Russia and abroad. In the course of legal proceedings on facts of mistaken identity and its consequences, forensic examinations are carried out in most cases. Depending on the type of biometric registration and identification system, forensic computer-technical, traceological, portrait, video technical examinations as well as forensic medical examination and other medicolegal examinations are assigned. The article gives an assessment of legality and scientific validity of performing forensic anthropometric examinations of photographs and video recordings of the suspects captured on them.

The System of Forensic Activity Digitalization Theory

The article examines the system of private theory of forensic activity digitalization from the standpoint of forensic expertology. The subject, objects, tasks of the theory and its place in forensic expertology are described. The paper presents the theory of forensic activity digitalization that can be attributed to several private theories, the provisions of which equally apply both to the process of expert examination in general and to expert studies of individual types of examinations as well. Two sections in the theory system are designated: forensic examination of digital footprints and information and computer support for forensic activity. The first section includes and considers the following: the nature of digital footprints, their properties and features and the mechanism of formation; forms of presentation and classification of digital footprints and their carriers as objects of forensic examinations; general tasks of digital footprints expert examination. The second section pays attention to the technologies of algorithmizing and digitalization of methods and techniques of forensic examination. The prospects for the introduction of neural networks to forensic examination and the related relevant problems are considered. In addition, the author notes changes in the methodology and technologies for developing expert methods in connection with the introduction of artificial intelligence algorithms. This section outlines the areas of application of neural networks for solving forensic problems. The reasons for erroneous conclusions related to application of neural networks in forensic examinations are analyzed. Particular attention is paid to the sources of model risk. To develop methods for solving typical expert problems based on neural networks it is proposed to create forensic datasets and repositories for consequent analysis and machine learning for various types of forensic examinations. The article also substantiates the need for new expert competencies: expert data analyst, expert data engineer and machine learning engineer.

Integration Approaches in Forensic Portrait Examination

The article reviews some actual issues of the theory and practice of the production of forensic portrait examinations: the tight deadlines of the preliminary investigation, the increased time expenditures to produce forensic video examination, the need for an integrated approach to the training of forensic portrait experts. The author proposes to revise some approaches to the training of forensic experts in the field of forensic portrait examinations. Along with the possibility of a comprehensive forensic examination, taking into consideration current needs of practice, more attention needs to be paid to software application for processing photo and video images processing in order to improve visual perception of the information displayed and to study montage marks and their detectability. All this will contribute to the evolvement of a portrait examiner as a specialist of double competence.

The Relationship between the Concepts of “Artificial Intelligence” and “Artificial Neural Networks” in Forensic Expertology

The article addresses the relationship between the concepts of “artificial intelligence” (AI) and “artificial neural networks” (ANNs) in forensic context. Over the past few years there has been some growing scientific interest in applying these technologies in forensic examination, which makes the issue of how these developments are currently impacting forensic practice and how they might influence it in the long term quite relevant. The identification of their specific characteristics is expected to facilitate a more efficient integration of AI and ANNs into forensic activities at the methodological, legal, and organizational levels. To illustrate the general relationship between artificial intelligence (AI) and neural networks, and to demonstrate how they differ, the author provides a brief historical overview of the development of AI concepts and a description of the operating principles of certain AI systems, specifically artificial neural networks. The author also proposes the ways to integrate AI and neural networks into forensic activities at both theoretical and practical levels.

On the Issue of Unification of Legislation on Forensic Examination in the Civil and Administrative Proceedings

The article deals with the comparative analysis of the procedure of forensic examination commissioning and carrying out in arbitration, civil and administrative legal proceedings. The author examines procedural codes regulating the expertise and identifies the differences in courts’ approaches to its commissioning and to judiciary powers, rights, and responsibilities of experts. Special attention is paid to court limitations regarding examination commissioning on its own initiative in the arbitral procedure as well as to its broader powers in civil and administrative proceedings.The article also analyzes the need to unify the legal regulation of forensic activities, which in the author’s opinion will lead to increased predictability and transparency of legal proceedings, improve the quality of expert opinions and reduce the risk of legal errors. The author emphasizes that, despite the differences in legislation, basic principles of carrying out forensic activities remain consistent, which makes the measures on procedural norms unification not only possible, but also the necessary ones to enhance effectiveness of legal proceedings.The paper proposes specific unification measures that will help eliminate existing legal uncertainties, improve the quality of justice, and create a more uniform judicial practice.

The Study Peculiarities of Market Valuation of Wheeled Vehicles in Operation

The article critically examines the common practice of wheeled vehicles valuation and substantiates complex forensic approaches and methods for determining their market value. Specific aspects of using a comparative approach to the valuation of wheeled vehicles are discussed, and the procedure for the calculation is substantiated.Basic framework of vehicles average price calculation reviewed in the article can be used in the set of forensic vehicle commodity examination methods, which are now under development.

On the Mathematical Modeling of a Fire Thermogasodynamic Pattern and Using a Priory Calculation of Fire Hazard Factors in Forensic Fire Examination

The article presents the disadvantages of the “risk analysis” methodology for fire safety assessment of buildings and its inadmissibility in forensic practice. The option of numerical modeling application for fire hazards evaluation in forensic fire-examination is analyzed.