Forensic Evidence Research Articles

Sexually transmitted infections in sexually abused children: an audit project to implement PCR tests in a child advocacy center in Türkiye

Background. Sexual abuse in children can sometimes result in sexually transmitted infections (STIs), which can serve as crucial forensic evidence. Although PCR methods are now accepted as the gold standard for STI screening, they have not yet widely replaced traditional culture methods in Türkiye. This study aims to assess the necessity of implementing PCR-based STI testing at Child Advocacy Centers in Türkiye, where such testing is not routinely available. Methods. Conducted between February and November 2023, this study included children who presented to the Child Advocacy Center of Marmara University Pendik Training and Research Hospital. High-risk victims were identified based on criteria including a history of penetrative sexual abuse and factors such as multiple perpetrators or significant age disparity. Serological tests and genital swabs were collected and analyzed using both bacterial culture methods and a comprehensive STI PCR panel. Results. The study included 20 victims, with a median age of 16 years. STI PCR testing detected pathogens in 19 out of 21 samples, including Chlamydia trachomatis (20%) and Neisseria gonorrhoeae (5%). In contrast, culture methods identified no sexually transmitted pathogens. Conclusion. PCR testing demonstrated significantly higher sensitivity for detecting STIs compared to traditional bacterial culture methods, as expected. Implementing PCR-based STI testing in Child Advocacy Centers is an urgent and essential need for providing an accurate diagnosis and robust forensic evidence, enhancing the care and legal protection of sexually abused children.

Score-based likelihood ratios for barefootprint evidence using deep learning features.

As the court put forward higher requirements for quantitative evaluation and scientific standards of forensic evidence, how to objectively and scientifically express identification opinions has become a challenge for traditional forensic identification methods. Score-based likelihood ratios are mathematical methods for quantitative evaluation of forensic evidence. However, due to the subtle differences in inter-class barefootprints, there is no automatic barefootprints matching algorithm with high accuracy under large-scale dataset validation, and there are few studies related to deep learning barefootprint features for evidence evaluation in court. Therefore, score-based likelihood ratios for barefootprint evidence using deep learning features are proposed by this paper. Firstly, the largest barefootprint dataset (BFD) is constructed, which contains 54,118 barefootprint images from 3000 individuals. Then, an automatic barefootprint feature extraction and matching algorithm is proposed, which achieves a retrieval accuracy of 98.4% on BFD and an AUC of 0.989 for barefootprint validation. Next, Cosine distance, Euclidean distance and Manhattan distance are employed to measure the comparison scores between intra-class and inter-class barefootprints using deep learning features in four dimensions of 64, 128, 512 and 1024, respectively. The performance of proposed model is evaluated by comparing the values and the Tippett plot. Finally, simulated crime scene barefootprint samples are constructed to verify the practical application of the proposed method, which provide further support for the quantitative evaluation of barefootprint evidence in court.

Decomposition dynamics and Calliphoridae succession in forest and urban environments of Constantine (Northeast of Algeria): implications for forensic entomology

ABSTRACT Forensic entomology serves a vital role in criminal investigations, contributing to the determination of time of colonization (TOC), minimum post-mortem interval (minPMI), and other forensic evidence related to the decomposition process. This study aimed to identify Calliphoridae species attracted to carcasses in two distinct locations in Algeria and to understand their role in forensic investigations. Two sites in Constantine were selected: a forest in Jebel Ouahch and an urban area in Chaabat Erssas. Two dog carcasses, an adult and a puppy, were monitored for decomposition stages. The puppy carcass reached the dry stage faster than the adult carcass, with decomposition rates varying between sites. A total of 594 Calliphoridae flies were collected, including Calliphora vicina, Calliphora vomitoria, Calliphora subalpina, Lucilia sericata, Lucilia illustris, Lucilia silvarum, and Chrysomya albiceps. These species were present in both locations, with Ch. albiceps being most prevalent, especially on the puppy carcass. Initial blowfly colonization occurred within four hours, with L. sericata and Ch. albiceps particularly abundant. This study underscores the importance of accurate species identification and environmental reconstruction in improving the precision of forensic estimates. Continued research on species phenology and the impacts of climate change will further enhance the applicability of forensic entomology in Algeria.

Understanding the Implications of Non-Accused DNA at Crime Scenes for Criminal Defence Lawyers

While DNA evidence has revolutionized criminal investigations, its presence in legal cases becomes problematic when the DNA of non-accused individuals is detected at crime scenes. This essay explores the issue of unintentional DNA transfer and its implications for defence attorneys. This study questions the prevailing assumption that DNA presence equates to guilt by analyzing a burglary case study, demonstrating how DNA can be unintentionally deposited by those not involved in the crime. The findings reveal the complexities surrounding forensic evidence, showing that individuals who haven't physically interacted with crime scene objects can still leave their DNA behind. This complexity underscores the need for lawyers to adopt a more nuanced perspective, emphasizing the importance of expert testimony, rigorous investigative methods, and contextual evaluations in accurately assessing the implications of DNA evidence within the judicial system. Understanding these intricacies is vital for police officers and legal professionals including judiciary to navigate carefully and sincerely cases where DNA evidence plays a critical role in proving or disproving the guilt of the accused person.

A comprehensive epidemiological assessment of female rape in São Paulo State, Brazil: trends, patterns, and implications for public health.

Sexual violence against women remains a global challenge, with Brazil exemplifying persistent issues despite legislative advancements. This study examined sexual violence within São Paulo state, Brazil's largest and economically affluent state, focusing on prevalence, patterns, forensic evidence, and health consequences. We analyzed 40,757 medical reports of alleged cases of rape against women available from the São Paulo Medical Legal Institute from 2014 to 2017. An increase in female rape cases was observed, reflecting broader societal trends, but underreporting, prevalent due to fear and stigma, underscored the need for multifaceted interventions. We also explored correlations between rape prevalence and the Human Development Index, highlighting disparities between urban and rural areas. Additionally, the study revealed concerning proportions of cases involving vulnerable victims, emphasizing the imperative for tailored interventions and legislative reforms. Furthermore, we demonstrated that only a small portion of medicolegal examinations were able to find evidence of sexual violence or recent sexual acts, necessary for conducting the criminal investigation of the alleged act. Therefore, despite challenges in forensic evidence collection, efforts to enhance medical examination protocols and awareness among professionals are crucial. Moreover, findings underscored the significant health consequences of rape, including unwanted pregnancies and sexually transmitted infections, necessitating comprehensive healthcare services for survivors. In conclusion, we reinforced that addressing sexual violence demands coordinated action, including legislative reforms, community engagement, and survivor-centered approaches, to create safer and more resilient communities.

Influence of Drugs and Toxins on Decomposition Dynamics: Forensic Implications

Drug and toxin-related deaths are common worldwide, making it essential to detect the postmortem concentration of various toxic substances at different stages of decomposition in a corpse. Indeed, determining the postmortem interval (PMI) and cause of death in an advanced stage of decomposed corpses has been a significant challenge in forensic investigations. Notably, the presence of drugs or toxins can have a significant impact on the microbial profile, potentially altering the succession of microbial communities and subsequent production of volatile organic compounds (VOCs), which, in turn, affect insect colonization patterns. This review aims to highlight the importance of investigating the interactions between drugs or toxins, microbial succession, VOC profiles, and insect behavior, which can provide valuable insights into forensic investigations as well as the ecological consequences of toxins occurring in decomposition. Overall, the detection of drugs and other toxins at different stages of decomposition can yield more precise forensic evidence, thereby enhancing the accuracy of PMI estimation and determination of the cause of death in decomposed remains.

Warnings from the West: Identification and Expert Evidence as Causes of Wrongful Convictions and the Implications for South Africa (Part 2)

In Part 1 of this study, the existing literature on eyewitness misidentification evidence as a cause of wrongful convictions, as well as adversarial safeguards upon which criminal justice systems rely to identify errors in fact-finding, are reviewed. In Part 2, a similar investigation is conducted of improperly applied and faulty forensic expert evidence in criminal trials in the comparator countries, and how such evidence contributes to legal and root causes of injustice. Parallels are drawn to the adversarial system as it functions in South Africa and predictions are offered regarding the possibility that in South Africa too, the reliance on questionable expert evidence and the sometimes over-reliance on valid expert evidence may lead to wrongful convictions. Worldwide, much effort has been invested in developing admissibility criteria for expert forensic evidence. In the United States of America, for example, more than 100 years of admissibility jurisprudence has been dedicated to developing admissibility standards that would filter out unreliable evidence. Yet our investigation reveals admissibility criteria have had less success than expected. We also investigate the abilities and inabilities of cross-examination and acquired defence expertise to reveal errors in forensic evidence. The article concludes with critical commentary on the way forward for the South African criminal justice system.

A Dirichlet Process Model for Directional-linear Data with Application to Bloodstain Pattern Analysis

Directional data require specialized models because of the non-Euclidean nature of their domain. When a directional variable is observed jointly with linear variables, modeling their dependence adds an additional layer of complexity. A Bayesian nonparametric approach is introduced to analyze directional-linear data. Firstly, the projected normal distribution is extended to model the joint distribution of linear variables and a directional variable with arbitrary dimension projected from a higher-dimensional augmented multivariate normal distribution. The new distribution is called the semi-projected normal distribution (SPN) and can be used as the mixture distribution in a Dirichlet process model to obtain a more flexible class of models for directional-linear data. Then, a conditional inverse-Wishart distribution is proposed as part of the prior distribution to address an identifiability issue inherited from the projected normal and preserve conjugacy with the SPN. The SPN mixture model shows superior performance in clustering on synthetic data compared to the semi-wrapped Gaussian model. The experiments show the ability of the SPN mixture model to characterize bloodstain patterns. A hierarchical Dirichlet process model with the SPN distribution is built to estimate the likelihood of bloodstain patterns under a posited causal mechanism for use in a likelihood ratio approach to the analysis of forensic bloodstain pattern evidence.

Organic fluorophores in developing latent fingerprints: an up-to-date review

AbstractFingerprints have been established as legitimate and critical forensic science evidence for identifying criminals beginning as early as the twentieth century. This article details the different types of fingerprints, the broad range of surfaces, and various development techniques available for on-site latent fingerprint collection, with fingerprint fidelity being of prime significance. Fluorescent imaging of latent finger-marks benefits from enhanced sensitivity, selectivity, and reduced reliance on instruments. The review focuses on the topical developments reported on small-molecule organic fluorophores which could be used to develop latent prints through powder, solution, and fuming approaches. These inexpensive luminophores extend wide emission profiles that span the visible spectrum to visualize the latent prints with exceptional resolution, free from any interference originating from the background surface. Further, the critical challenges and prospective scope for future research developments to improve the detection of latent fingerprints using small-molecule fluorophores are also discussed. Graphical abstract

Forensic STR and SNP Genotyping of Formalin-Fixed Skeleton Samples With Illumina's ForenSeq System.

Formalin fixatives are widely used in forensics to preserve tissues. However, extracting high-quality genomic DNA from formalin-fixed samples is challenging. Traditional short tandem repeat (STR) analysis using capillary electrophoresis (CE) for forensic DNA typing frequently results in failure. Massively parallel sequencing (MPS) can handle many samples and thousands of genetic markers, usually single-nucleotide polymorphisms (SNPs) and STRs, in a single test. Thus, it is useful for assessing highly deteriorated forensic evidence. Few studies have examined the effectiveness of STRs and SNPs genotyping of formalin-fixed skeletons using MPS. In this study, 55 skeletal samples from 5 individuals that were treated under different formalin fixation times (5-75 days) were examined and sequenced using the ForenSeq DNA Signature Prep Kit on the Illumina MiSeq FGX platform. The results showed that as the duration of formalin fixation increased, the detection rates of STRs and SNPs gradually decreased. After 75 days of fixation, the average detection rates for STRs and SNPs were 4% and 10%, respectively. The cumulative discrimination power (CDP) of individual identification SNPs (iiSNPs) was >0.9999 on the 45th day. However, the CDP of STRs was 0.9930 on the 22nd day. Low detection rates were observed for six STRs (D1S1656, PentaE, D22S1045, PentaD, DX8378 and DX10103) and five SNPs (rs2920816, rs354439, rs1736442, rs338882 and rs1031825). In conclusion, DNA extracted from formalin-fixed skeletons decomposes rapidly over time, and MPS technology can be a useful tool for detecting forensic genetic markers in such samples.

Flaws in the Bharatiya Nagarik Suraksha Sanhita, 2023 (BNSS) – A Critical Study

The successful execution and overall impact of the Bharatiya Nagarik Suraksha Sanhita, 2023 (BNSS), may face significant challenges due to various pressing issues. Among these are vague protocols surrounding private arrests, mixed terminology related to police custody, and unclear guidelines regarding community service as a penalty. Furthermore, the BNSS fails to provide clear directions for filing electronic FIRs, employing audio-visual techniques for witness examinations, and outlining the process for reimbursing witness costs. Concerns also arise from the absence of well-defined grounds for bail cancellation, inadequate enforcement of the Witness Protection Scheme, and procedural deficiencies in the collection of forensic evidence. Furthermore, the BNSS fails to address alternative dispute resolution methods and relies on insufficient resources, such as officers' personal mobile phones, for important tasks like video documentation during search and seizure operations. These flaws have the potential to undermine the intended objectives of the BNSS and pose significant operational challenges.

Forensic evidence in sexual assault laws: a content analysis of state statutes in the United States of America

ABSTRACT The collection of forensic evidence is perceived to be a panacea in sexual assault investigations and criminal prosecutions. However, research has shown an alarmingly different reality, whereby forensic evidence is rarely available, collected, tested, or available during criminal investigations and court procedures. Regardless, many states have begun implementing new policies to improve the collection and preservation of forensic evidence. This study explores the state of forensic evidence policies and legislation throughout the United States of America as they relate to sexual assaults through a content analysis of the nation’s state statutes. Following the 2016 legislative session statutes were found to be organized into two themes: 1) survivor-related statutes and 2) offender-related statutes. Though innovative forensic evidence policies were observed, much of this legislation appeared to be inconsistent with the reality of sexual assault and is best described as vague and inadequate. In view of these observations, this paper discusses policy implications and areas of future research.

Best Practices in the Nursing Care of Patients With Injuries From Violence: An Integrative Review.

The number of patients who have experienced violence is increasing worldwide. These patients have specific psychosocial and forensic needs and can present unique challenges to the health care workers caring for them. To identify best practices for the care of patients with injuries from violence in the emergency department or inpatient setting. The framework for integrative reviews by Whittemore and Knafl was used to conduct a literature search in MEDLINE, CINAHL, and ProQuest Nursing and Allied Health databases. Fourteen qualitative, quantitative, and mixed-methods studies from peer-reviewed journals were included in the review. Themes included identifying patients as survivors of intimate partner violence or child abuse, the need to collect forensic evidence, the need for emotional support of patients and their loved ones, support for health care workers caring for patients with injuries from violence, prevention of further violence, and the challenges of caring for patients with injuries from violence with concurrent substance use disorders. Best practices for these aspects of care are summarized on the basis of literature analysis. Screening procedures are needed to identify survivors of intimate partner violence and child abuse. Forensic evidence preservation policies should be in place. For survivors of sexual assault, a sexual assault nurse examiner should be available. Hospital systems should provide psychosocial resources for patients' and health care workers' mental health, implement violence reduction programs, and provide bias training. More research is needed to determine efficacy of care models and best practice.

Quantifying variation in the physical size of footwear test impressions

The analysis of forensic footwear evidence often requires the preparation of test impressions created under controlled laboratory conditions. When these test impressions are compared to questioned impressions, (dis)agreement in physical size is an important attribute that must be evaluated and documented. Integral to this comparison is an understanding of the variation that may exist between replicate test impressions, and test impressions created using different methods. The aim of this study was to empirically characterize the variation that exists within and between test impressions prepared using a static benchtop and a dynamic walking method, as well as explore the potential influence of the wearer’s foot size when using the walking method. To examine this variation, twenty-three participants were recruited to prepare test impressions of two different shoe makes and models in four different manufacturer’s sizes. Five replicate benchtop impressions per make/model/size and three replicate walking impressions per participant/make/model/size were created, resulting in approximately 550 test samples, to which an additional 150 quality control copies were blindly added, resulting in almost 700 processed test impressions. Using reproducible and reliable ground control points, the physical size of toe-to-heel length and medial-to-lateral ball of the toe width measurements were collected and compared. For the shoe make/models examined in this study, a systematic bias was observed between benchtop and walking impressions, such that benchtop impressions were almost always longer and narrower than walking impressions, and that within the walking method, physical size differences vary with foot/shoe size mismatch. Of the experimental shoes and groups examined in this study, the variation in toe-to-heel length measurements between benchtop and walking impressions was greatest when the shoe was two sizes smaller than the foot, resulting in a maximum physical size difference of 4.18 mm for a Nike® Downshifter 11 outsole. Similarly, when comparing the variation in toe-to-heel length measurements between walking impressions created using a correctly-fitted shoe versus a shoe that was two sizes smaller than the wearer’s foot, a maximum physical size difference of 3.25 mm was observed. Based on these findings, best practice suggests that footwear analysts document the foot size of the wearer preparing walking test impressions, refrain from using benchtop impressions to form opinions about physical size consistency/differences, and to be cognizant that a large mismatch between foot/shoe size when creating walking impressions can lead to length differences greater than 3.0 mm.

Automated comparison and evaluation of striated cutting plier toolmarks on metal wires

Toolmarks examination validity and subjectivity have come under scrutiny. This research focuses on the case of cutting plier marks. This paper presents an automatic comparison method and assesses its performance. It is designed to assign a weight to the forensic evidence (i.e, a comparison between toolmarks) with a likelihood ratio (LR). 3D topographies are acquired and treated to be compared using a set of correlation metrics. A machine learning algorithm combines comparison metrics and enables LR computation. Pliers of various brands and models were used to study the variability both within and between tools. We explained why the specific zone (area along the blade) has to be chosen to build the within-source variability and how the between-source variability can be built in different scenarios. Misleading evidence rates between 0 % and 4 % have been measured and it demonstrates the accuracy of the method when applied on the pliers used.

Quantitative matching of forensic evidence fragments using fracture surface topography and statistical learning

The complex jagged trajectory of fractured surfaces of two pieces of forensic evidence is used to recognize a “match” by using comparative microscopy and tactile pattern analysis. The material intrinsic properties and microstructures, as well as the exposure history of external forces on a fragment of forensic evidence have the premise of uniqueness at a relevant microscopic length scale (about 2–3 grains for cleavage fracture), wherein the statistics of the fracture surface become non-self-affine. We utilize these unique features to quantitatively describe the microscopic aspects of fracture surfaces for forensic comparisons, employing spectral analysis of the topography mapped by three-dimensional microscopy. Multivariate statistical learning tools are used to classify articles and result in near-perfect identification of a “match” and “non-match” among candidate forensic specimens. The framework has the potential for forensic application across a broad range of fractured materials and toolmarks, of diverse texture and mechanical properties.

Factors Associated With Legal Decisions of Nonfatal Strangulation Cases With Forensic Evidence

This study examines the influence of offender, victim, and case characteristics along with available forensic evidence on legal outcomes of nonfatal strangulation (NFS) cases. Research points to the importance of NFS forensic evidence collection to corroborate the attack during legal proceedings. However, little is known regarding the factors associated with legal decisions for NFS cases with forensic evidence. Law enforcement reports, forensic medical examinations, and legal outcomes for 63 NFS cases in Florida were analyzed. Findings have implications for the criminal justice system, as forensic medical exams can be used to collect valuable evidence to support prosecution outcomes.

The Role of Digital Forensics in Criminal Investigations: An Analysis of Electronic Evidence in the Indonesian Legal System

Research on the use of digital forensic evidence in the process of investigating criminal acts, especially those carried out by the Police with their legal structure capabilities, aims to find out and analyze the extent to which evidence produced through digital forensics plays an important role in the process of proving criminal acts, the results of which become electronic evidence that has the strength of evidence in the applicable criminal procedural law. The type of research is normative (doctrinal), namely research that views law as building a system of norms. Digital forensics is an important instrument that helps investigators carry out research and investigation tasks, and it is an absolute requirement that must be met so that electronic documents can be used as evidence from the start of investigations, inquiries, prosecutions, and trials. The role of digital forensics in uncovering a criminal case starts from the preliminary stage, where investigators begin to collect evidence and electronic evidence assisted by one or more digital forensic experts. Digital forensics from the investigation stage is used to find material truth in every process of proving a criminal act.

Forensic Science and How Statistics Can Help It

ABSTRACTThe persistent issue of wrongful convictions in the United States emphasizes the need for scrutiny and improvement of the criminal justice system. While statistical methods for the evaluation of forensic evidence, including glass, fingerprints, and deoxyribonucleic acid, have significantly contributed to solving intricate crimes, there is a notable lack of national‐level standards to ensure the appropriate application of statistics in forensic investigations. We discuss the obstacles in the application of statistics in court and emphasize the importance of making statistical interpretation accessible to non‐statisticians, especially those who make decisions about potentially innocent individuals. We investigate the use and misuse of statistical methods in crime investigations, in particular the likelihood ratio approach. We further describe the use of graphical models, where hypotheses and evidence can be represented as nodes connected by arrows signifying association or causality. We emphasize the advantages of special graph structures, such as object‐oriented Bayesian networks and chain event graphs, which allow for the concurrent examination of evidence of various nature.

Evaluating the Forensic Inferences of Oral Nicotine Ingestion: Autopsy Case Review, Animal Experimentation, and Legal Implications

Nicotine, a highly lipophilic alkaloid derived from Nicotiana tabacum and Nicotiana rustica, can be lethal even in small doses when ingested in concentrated forms like e-cigarette liquids. This study examined a murder case in South Korea where a 52-year-old man was allegedly killed by oral administration of nicotine. Despite the absence of typical signs, such as chemical burns or vomiting, the case posed questions about the lethal concentration of nicotine and the presence of gastrointestinal symptoms in nicotine poisoning. Through literature review, autopsy analysis, and animal experiments, this study evaluated the forensic evidence presented in court. The results indicated that lethal nicotine levels could be lower than established previously, and death could occur without gastrointestinal injury or vomiting. Our findings supported the court's conviction decision, emphasizing the variability of symptoms in nicotine toxicity and the importance of scientific evidence in legal proceedings. The results of this study highlight the role of forensic medicine in clarifying scientific uncertainties in judicial contexts, particularly in cases involving toxic substances.