Forensic Interest Research Articles

On forensic likelihood ratios from low-coverage sequencing.

Advances in sequencing technology are allowing forensic scientists to access genetic information from increasingly challenging samples. A recently published computational approach, IBDGem, analyzes sequencing reads, including from low-coverage samples, in order to arrive at likelihood ratios for human identification. Here, we show that likelihood ratios produced by IBDGem are best interpreted as testing a null hypothesis different from the traditional one used in a forensic genetics context. In particular, rather than testing the hypothesis that the sample comes from a person unrelated to the person of interest, IBDGem tests the hypothesis that the sample comes from an individual who is included in the reference database used to run the method. This null hypothesis is not generally of forensic interest, because the defense hypothesis is not typically that the evidence comes from an individual included in a reference database. Moreover, the computed likelihood ratios can be much larger than likelihood ratios computed for the standard forensic null hypothesis, often by many orders of magnitude, thus potentially creating an impression of stronger evidence for identity than is warranted. We lay out this result and illustrate it with examples, giving suggestions for directions that might lead to likelihood ratios that test the typical defense hypothesis.

Introduction to Nuclear Forensics Analysis Techniques

Abstract Nuclear forensics is the interdisciplinary branch of forensic science that deals with the analysis and examination of nuclear or other radioactive materials, or of evidence that is contaminated with radionuclides in the context of legal proceedings under international or national law related to nuclear security. To control and avoid the threat of terrorism posed by illicit trafficking and mismanagement, nuclear and other radioactive materials must be strictly regulated. Thus, the goal of nuclear forensic analysis is to discover what radioactive materials were confiscated, how, when, and where they were manufactured, and what their intended applications were. Nuclear forensic scientist has a wide array of analytical tools to use for detecting signatures in radioactive materials. These individual techniques can be sorted into three broad categories: bulk analysis tools, imaging tools, and micro-analysis tools. Particular interest in nuclear forensics is particle morphology, isotopic composition of a material, presence of impurities, and microstructure. These properties can vary between materials of different origins due to varying processing or geological conditions, thus, allowing for discrimination of material history and prediction of provenance. This review article presents many key analytical techniques and discusses the main application and challenges of the most common techniques currently used in nuclear forensics analysis.

Identifying Persons of Interest in Digital Forensics Using NLP-Based AI

The field of digital forensics relies on expertise from multiple domains, including computer science, criminology, and law. It also relies on different toolsets and an analyst’s expertise to parse enormous amounts of user-generated data to find clues that help crack a case. This process of investigative analysis is often done manually. Artificial Intelligence (AI) can provide practical solutions to efficiently mine enormous amounts of data to find useful patterns that can be leveraged to investigate crimes. Natural Language Processing (NLP) is a subdomain of research under AI that deals with problems involving unstructured data, specifically language. The domain of NLP includes several tools to parse text, including topic modeling, pairwise correlation, word vector cosine distance measurement, and sentiment analysis. In this research, we propose a digital forensic investigative technique that uses an ensemble of NLP tools to identify a person of interest list based on a corpus of text. Our proposed method serves as a type of human feature reduction, where a total pool of suspects is filtered down to a short list of candidates who possess a higher correlation with the crime being investigated.

Mass spectrometry proteomic profiling of postmortem human muscle degradation for PMI estimation

The discovery of new methods for determining the post-mortem interval is of significant forensic interest. Mass spectrometry has enhanced the accuracy of assessing post-mortem protein decay, with skeletal muscle being the most studied substrate due to its intrinsic properties of postmortem decay. In this pilot study, human skeletal muscle tissue (iliopsoas) was harvested and allowed to decay under controlled temperature and humidity conditions at predetermined intervals.The samples were analyzed using mass spectrometry proteomics for both qualitative and quantitative evaluation of proteins and peptides. Candidate proteins were validated through immunoblotting.The results were significant, identifying several proteins that could aid in estimating the post-mortem interval. Notably, PLIN4, MYOZ2, SYNPO2, and BAG3 were validated by immunoblotting over a broader range of experimental points and temperatures. Furthermore, human results were compared with animal muscle samples from a previous study, revealing similarities in decomposition kinetics.This analysis of human samples marks a step forward in the potential forensic application of proteomic evaluation by mass spectrometry.

Postmortem interval estimation of human skeletonized remains through luminol chemiluminescence

Postmortem interval (PMI) estimation represents a significant challenge in the forensic sciences, particularly when dealing with human skeletal remains. A screening protocol for distinguishing possible remains of forensic interest is a crucial tool for judicial purposes. In this context, luminol chemiluminescence emerges as a promising method, with low overall costs and required time. This method is primarily used as a presumptive test, based on the understanding that the intensity of the chemiluminescence reactions decreases with an increase in the postmortem interval, thus underlining its practical implications.This research aims to expand previous research on the potential of luminol chemiluminescence, evaluating its usefulness in estimating PMI. Our sample comprised 239 human clavicles, with known PMI. The luminol solution was sprayed on each powder bone sample in a dark room, observed by the naked eye and photographed. The intensity of the chemiluminescence reaction was measured using a binary and a 5-level scale.The present results reveal that this method is a suitable tool for PMI estimation as a presumptive test, reducing time and costs in criminal investigations. The findings underscore the high sensitivity of luminol chemiluminescence for detecting recent PMI but also highlight a notable incidence of false positives. Thus, our results confirm luminol chemiluminescence as a powerful tool for dating time of death, particularly for identifying forensic relevant remains. Still, the relatively low specificity indicates that it should be complemented with additional tests for further confirmation and scientific validation of the remains’ forensic relevance.

“The Study Of Eruption Of Teeth In Children From Birth To 12 Years Of Age In Western Maharashtra Region.”

Human beings show 2 sets of dentition- deciduous and permanent2. Variation of tooth has been an enduring interest to clinical practitioner as well as from anthropological and forensic point of view7 . These variations in the form of teeth are characteristics of race, are of anthropological, genetic and forensic interest.2,7hence studies have been done using teeth for age, sex determination1,8 . As existing eruption schedule of dentition is based on western population this study is done in western Maharashtra region to find out variation in time number, form and pattern of eruption in deciduos and permanent teeth as well as in males and females.

3D printing and CBCT anatomical reproducibility assessment in forensic scenarios

IntroductionThe scientific community highlighted the relevance of 3D physical models since the beginning of the XXI century, complementary to three-dimensional(3D) digital volume by computer tomography, to support court discussions on medico-legal issues. The recreation of 3D evidence can be an important tool for investigators and experts, providing a better understanding of the causes and circumstances of the events involved in a crime. ObjectiveThe present study aims to assess the reproducibility of 3D printed and 3D tomographic volumes generated from mandibles following simulated forensic injuries, highlighting the recreation of crime tools. Material and methodsConcerning the study design presented, data collection was performed in three phases. Nine simulated injuries of forensic interest were selected (phase1) and all the mandibles were scanned tomographically, individually, by Cone Beam Computed Tomography CBCT (phase 2). Then, in phase 3, the DICOM images were used for 3D printing with the Ender 3® printer by the Fused Deposition Modeling (FDM) technique. The data analysis followed two procedures: the comparison between the artificial mandible and 3D tomographic volume (AT) and the comparison between the artificial mandible and 3D printed volume, or the copy (AC). Data were analyzed using T-Student and ICC tests and presented in Bland-Altman plots. ConclusionThe analogic technique applied in 3D printed volume, when compared with computerized technique, using 3D digital images and measurement, showed to be accurate and reproducible. Further studies are needed in search of standardization for three-dimensional measurements in digitized and printed volumes.

Evaluation of the effect of clonazepam and its metabolites on the life cycle of Megaselia scalaris (Loew) (Diptera: Phoridae)

Fly colonization patterns and development are crucial in estimating the post-mortem interval (PMI) of decomposing corpses. Understanding the potential effects of xenobiotics on species development in cadaveric entomofauna is essential for accurate PMI estimation, given their presence in decomposing bodies. Benzodiazepines, commonly prescribed for their anxiolytic, hypnotic, and muscle relaxant effects, are of forensic interest due to their potential for abuse, dependence, intoxication, and overdose-related deaths. This study aimed to explore the effect of clonazepam and its metabolites on Megaselia scalaris, a species commonly used to estimate PMI, the alteration of which could impact the accuracy of said estimation. The S9 biotransformation fraction, an in vitro model consisting of an array of metabolic enzymes, was used to generate phase I and II metabolites for evaluating their effect on M. scalaris development, representing an innovative approach to this type of study. Megaselia scalaris larvae were reared in synthetic growth media under controlled conditions. The study compared different groups: control, clonazepam, and clonazepam with S9 fraction. Larvae were measured daily to determine growth rate, and clonazepam concentrations were analyzed using HPLC-DAD. Results showed that larvae grown in media containing clonazepam or clonazepam with S9 fraction developed faster than control larvae, reaching their pupal stage earlier. Growth rates were also altered in treated groups. In conclusion, the presence of clonazepam and its metabolites accelerated the life cycle of M. scalaris, potentially impacting the accuracy of PMI estimation. These findings underscore the importance of considering xenobiotics in forensic entomological studies for precise post-mortem interval determination.

What do we know about the perpetrators of sexual homicide of adult victims? A systematic review and qualitative meta-synthesis

Introduction: sexual homicide is defined as lethal violence associated with sexual elements or motivations, predominantly perpetrated by men against women. Despite being a less frequent crime, there is a growing clinical and forensic interest in its specificities and the characteristics of the aggressor. Objective: to review the scientific literature on men who commit sexual homicide against adult victims. Methods: systematic review with MeSH ((“Sex Offenses”[Mesh]) AND “Homicide”[Mesh]) in the databases of MEDLINE, LILACS, MENDELEY and SciELO, between 1992 and 2023. The PICO strategy was used with the studied population (male sexual offenders), intervention (homicide of adult victims), context (sexual violence), and outcome (potential relationship between the issues). The stages of article selection and analysis involved two independent researchers. Original studies were included, excluding reviews, editorials, conference proceedings, books and chapters, theses, and dissertations. The selected articles were presented through qualitative meta-synthesis. Results: of the 70 selected articles, 66 articles (94.2%) adopted quantitative methods, 2 (2.9%) qualitative design, and 2 (2.9%) case reports. We found 41 articles (58.6%) conducted in North America and 22 articles (31.4%) in Europe, totaling 63 articles (90.0%). Another five articles (7.1%) were from Asia, one (1.4%) from Africa, and one (1.4%) from Oceania. In 52 articles (74.3%), there was an emphasis on aspects related to psychiatric, behavioral, or psychological disorders of the perpetrator, sexual sadism, or forms of sexual violence or lethal outcomes employed. Conclusion: sexual homicidal men possess characteristics that set them apart from other homicidal offenders or those who commit sexual violence, directing their crimes towards a heterogeneous group of adult victims. Studies have focused on the psychiatric and behavioral disorders of the perpetrator, as well as the relationship with traumatic experiences in childhood.

New alginate-gelatine method for casting of staining inside firearm barrels

Contact shots to the head often leave behind biological traces inside firearm barrels, a phenomenon of great forensic interest. Until now, the visualization and preservation of these traces presented a significant challenge, lacking a reliable method. This study addresses this gap by searching for a suitable method to extract the traces within a casting. Using alginate or gelatine as suitable materials, the results were hampered by serious adhesion issues and their extraction out of the firearm barrel was impeded. Finally, the combination of 11% gelatine with 1% alginate, introduced into the barrel around a ‘central spine’, succeeded to consistently produce replicable castings. Experimental contact shots displayed a distinct staining gradient from the muzzle to the rear of the barrel, as revealed through endoscopy and proved in the macroscopic casting. The technique proved effective for various common handgun barrels and successfully preserved blood and gunshot residue (GSR) patterns within the barrel. This method offers the dual benefits of visually mapping staining patterns and securing localized samples for targeted molecular genetic analysis in forensic investigations.

Megaselia scalaris (Diptera: Phoridae) development and behaviour under fluoxetine effect and Calliphora vicina (Diptera: Calliphoridae) presence

Megaselia scalaris Loew (Diptera: Phoridae) and Calliphora vicina Robineau-Desvoidy (Diptera: Calliphoridae) are species of medical and forensic interest. Scuttle flies can eat carrion but also behave as a facultative parasitoid of other organisms. This study evaluated the effect of fluoxetine on the development of M. scalaris, and also the feeding behavior of the scuttle flies. For this, these flies were reared on artificial fodder with 2000 mg/kg of fluoxetine and also larvae of blue bottle flies on third stage were added. A control was used for each analysis. Daily observations were performed from the beginning to the end of the experiments. The duration of life cycle, body length, grosso modo external morphology and sex ratio were evaluated. Results indicated that development of M. scalaris was not affected by fluoxetine. The duration of stages, body length and external morphology did not show differences between fluoxetine and control groups. In addition, scuttle flies did not behave as parasites of blue bottle flies in their larval advanced stage and their presence did not interference on the development of M. scalaris. In conclusion, no alteration was observed on the development of M. scalaris at the dose of fluoxetine used and scuttle flies presence did not necessarily imply predation or parasitism of C. vicina larvae. Therefore, the current study provides data that could be applied in forensic entomological research or in forensic expertise.

New geographic location data on the occurrence and abundance of carrion insects of forensic interest.

The world's forensic entomologists have much in common. They face similar research challenges, apply the same scientific methodology, study the same kinds of evidence, and access global research databases. Nevertheless, some regional heterogeneity inevitably exists. For most countries, and particularly those that have complex and diverse ecosystems, the current priority is to stimulate use of forensic entomology by establishing open access databases with time series data using standardised protocols for occurrence, abundance, distribution, niche preferences, life cycle, and identification characteristics for the key regional species that may be encountered in forensic entomology cases. Even in countries where forensic entomology is routinely used as a tool in reconstructing the history of corpses found on crime scenes in accordance with principles found in the rapidly developing body of literature, there is still much to learn about forensically useful insects. Examples of regional gaps include the taxonomy of lesser-known carrion insect species, seasonal occurrence of carrion species in the country's various geographical regions, and rates of development of the local species modeled in the many site situations of forensic interest. The first published study of carrion insects found in Athens, Greece published in this journal is an example of entomologists in a region taking the necessary first step towards establishing baseline data about native and introduced species and hence, physiological and behavioural responses to local environmental conditions, including life cycles and likelihood of occurrence or absence in the region.

Structural segregation in GSR from mercuric primers. A preliminary study

Since the second half of the XX century, primer mixtures based on mercury fulminate have become a rare occurrence on small ammunition markets in Western Europe and North America. As a consequence, Hg-containing gunshot residue (GSR) particles have not been as deeply investigated as residues from lead-based primer mixtures. As a matter of fact, no mention of GSR particles from mercuric primers is made by the current ASTM standard procedure for gunshot residue analysis. However, those laboratories dealing with ammunition and firearms produced in Eastern Europe or Asia still have a forensic interest in Hg-containing GSR. In this paper, a brief description of chemical composition and inner morphology of GSR particles from three different mercuric primers is reported. Regarding composition, arguments are given to promote SbSnHg residues to Characteristic of GSR particles when mercuric primers are discharged. From a morphological point of view, presence of inner nodules and other inhomogeneities were shown in GSR particles milled in a FIB/SEM. Moreover, mercury vaporization under the electron beam was observed for a particle reduced to a lamella. Mercury evanescence in GSR was interpreted in terms of mercury segregation during particle formation and higher mobility of Hg atoms in presence of defects (vacancies) in a strained lattice.

Dating Skin Lesions of Forensic Interest by Immunohistochemistry and Immunofluorescence Techniques: A Scoping Literature Review.

Wound age estimation is a significant issue in forensic pathology. Although various methods have been evaluated, no gold standard system or model has been proposed, and accurate injury time estimation is still challenging. The distinction between vital skin wounds-i.e., ante-mortem lesions-and skin alterations that occur after death is a crucial goal in forensic pathology. Once the vitality of the wound has been confirmed, the assessment of the post-trauma interval (PTI) is also fundamental in establishing the causal relationship between the traumatic event and death. The most frequently used techniques in research studies are biochemistry, molecular biology, and immunohistochemistry (IHC). Biochemical methods take advantage of the chemical and physical techniques. A systematic literature search of studies started on 18 February 2023. The search was conducted in the main databases for biomedical literature, i.e., PubMed and Scopus, for papers published between 1973 and 2022, focusing on different techniques of immunohistochemistry and immunofluorescence (IF) for estimating the PTI of skin wounds. The present study involves a comprehensive and structured analysis of the existing literature to provide a detailed and comprehensive overview of the different IHC techniques used to date skin lesions, synthesize the available evidence, critically evaluate the methodologies, and eventually draw meaningful conclusions about the reliability and effectiveness of the different markers that have been discovered and used in wound age estimation.

Automatic Detection of Object-Based Video Forgery Using Various Groups of Pictures (GOP)

In recent years, there has been a lot of interest in detecting object-based video forgeries. There has been a lack of satisfactory performance with object-based forgery detectors until recently since a majority of them are still based on handcrafted features. There has been a great deal of interest in passive video forensics in recent years. Forgery of video encoded with advanced codec frameworks remains one of the biggest challenges in object-based forgery research. An object-based forgery detection approach is presented in this paper. To evaluate the proposed method, a derived test dataset of variable video lengths and frame sizes is also used in addition to the SYSU-OBJFORG dataset. This process's efficacy is verified by comparing its results with other methods. When tested on datasets with degraded-quality videos, the proposed framework performed better in real-life scenarios.

Stereoselective Voltammetric Biosensor for Myo-Inositol and D-Chiro-Inositol Recognition.

This paper describes the development of a simple voltammetric biosensor for the stereoselective discrimination of myo-inositol (myo-Ins) and D-chiro-inositol (D-chiro-Ins) by means of bovine serum albumin (BSA) adsorption onto a multi-walled carbon nanotube (MWCNT) graphite screen-printed electrode (MWCNT-GSPE), previously functionalized by the electropolymerization of methylene blue (MB). After a morphological characterization, the enantioselective biosensor platform was electrochemically characterized after each modification step by differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS). The results show that the binding affinity between myo-Ins and BSA was higher than that between D-chiro-Ins and BSA, confirming the different interactions exhibited by the novel BSA/MB/MWCNT/GSPE platform towards the two diastereoisomers. The biosensor showed a linear response towards both stereoisomers in the range of 2-100 μM, with LODs of 0.5 and 1 μM for myo-Ins and D-chiro-Ins, respectively. Moreover, a stereoselectivity coefficient α of 1.6 was found, with association constants of 0.90 and 0.79, for the two stereoisomers, respectively. Lastly, the proposed biosensor allowed for the determination of the stereoisomeric composition of myo-/D-chiro-Ins mixtures in commercial pharmaceutical preparations, and thus, it is expected to be successfully applied in the chiral analysis of pharmaceuticals and illicit drugs of forensic interest.

Linepithema humile (Mayr, 1868) (Hymenoptera, Formicidae), a new species associated with human cadavers

As it concerns the use of Entomology in forensic practice, this paper presents for the first time a case in which Linepithema humile (Hymenoptera: Formicidae) was found to be associated with human corpses. The species was collected in Murcia province (SE Spain) from the body of a middle-aged woman in advanced decomposition stage found indoors in unhygienic housing conditions. In addition to such species, specimens belonging to Calliphora vicina, Muscina stabulans, Musca sp. and Synthesiomyia nudiseta (Diptera) were also collected at the scene. These entomological specimens were found to be valuable for estimating the minimum postmortem interval. The occurrence of Linepithema humile reported here for the first time in a forensic case enhances the global list of insects of forensic interest.

Use of strontium isotope ratios in potential geolocation of Ajnala skeletal remains: a forensic archeological study.

Stable isotope methods for provenance of unidentified human remains are relatively a newer field of enquiry in forensic archeology. It is of great interest for forensic experts these days. The application of strontium isotope analyses for estimating geolocation of archeological remains is of great interest in bioarcheology and modern forensics. The strontium (Sr) isotope composition of human bones and teeth has been widely used to reconstruct an individual's geo-affiliation, residential mobility, and migration history. Thousands of unknown human remains, reportedly belonging to 282 Indian soldiers of 26th Native Bengal regiment and killed in 1857, were exhumed non-scientifically from an abandoned well situated underneath a religious structure at Ajnala (Amritsar, India). Whether these remains belonged to the individuals, local or non-local to the site, was the important forensic archeological question to be answered by doing their thorough forensic anthropological examinations. In the present study, 27 mandibular teeth (18s molars, 6 first molars, and 3 premolars) collected from the Ajnala skeletal assemblage were processed for strontium isotope analysis, and the measured ratios were compared with published isotope baseline data to estimate the locality status of these remains. The Sr isotopic values were concentrated in the range of 0.7175 to 0.7270. The comparative analysis of isotopic ratios revealed that most individuals buried in the Ajnala well have 87Sr/86Sr values close to the river as well as groundwater of the Gangetic plain (less radiogenic 87Sr/86Sr ~ 0.716); most likely originated near Varanasi (Uttar Pradesh, India) region, whereas the individuals with higher 87Sr/86Sr ratios (~ 0.7200) probably resided in the West Bengal and Bihar areas where the river as well as groundwater of the Gangetic plain is relatively more radiogenic. Thus, the strontium isotope results reveal that the Ajnala individuals did not grow up or live in the Amritsar region during their childhood, and this observation complemented the previous forensic anthropological and molecular findings. There is very little Indian data on the bioavailable strontium, so the inferences from the present study estimating Sr isotope abundances are expected to provide baseline data for future forensic provenance studies that will contribute to the global efforts of mapping Sr isotope variations by the isotope community.

Portable x‐ray fluorescence as a tool for assessing electric marks in forensic evaluation

AbstractPortable x‐ray fluorescence (XRF) is a reliable, rapid and noninvasive technique. Recently, it has been used in a wide variety of fields where the sample must still be available after examination or when qualitative information on chemical composition is needed quickly to perform more detailed studies. These properties also make it suitable for forensic investigations, as shown by some recent reports. In the present work, a systematic evaluation of metal micro traces in electric marks was performed in a case of death by electrocution (high‐voltage current). The results are promising, as XRF has been shown to be a suitable tool not only for skin fragments but also for graphite adhesive tapes placed on the body skin areas of forensic interest and then analyzed. The latter finding proves that skin samples at autopsy are not the only valuable sampling method, thus paving the way for the application of XRF in the diagnosis of electrical injuries in living individuals as well.

Dashcam forensic investigation guidelines

Dashboard cameras (“dashcams”) have become an important in-car accessory used to record audio and visual footage of car journeys. Dashcams appear more often in digital investigations and will become more prevalent with the growth of autonomous vehicles. The audio/video footage produced by dashcams contain important items of evidence, including the routes followed by the motor vehicle, video footage of the road ahead, the road behind and the cabin, as well as audio footage of conversations within the car.However, there exist no tools or guidelines on how these devices should be investigated, this could lead to cases of miscarriage of justice. This paper provides an overview of the key features of forensic interest within a dashcam device, followed by guidance on how to respond at a crime scene which involves a dashcam device and in particular how to preserve the evidence found therein.This is followed by with guidelines on how to acquire the evidence in a dashcam device, the problems and challenges involved in the examination and analysis of dashcams, before finishing with a discussion around the reporting and presentation of dashcam evidence.