Forensic Sciences

Cannabis use is widespread and is one of the most common drugs encountered in forensic-related analysis (antemortem and postmortem cases). However, the correlation between illicit cannabis use and death is rarely investigated, even while taking into consideration its role in the central nervous system depression and cardiovascular disorders. Few studies have discussed other non-blood specimens; this has brought a special interest in analyzing THC and its metabolites in different body parts in order to make precise forensic decisions. Herein, we are investigating the presence of Δ⁹-tetrahydrocannabinol (THC) and its metabolites:(11-hydroxy-Δ⁹-tetrahydrocannabinol (THC-OH) and 11-nor-Δ⁹- tetrahydrocannabinol-9-carboxy (THC-COOH)) in different postmortem specimens. Forty-three cases of bodily fluids and tissue post-mortem samples, previously found to be cannabinoid-positive were analyzed in the current investigation using alkaline hydrolysis followed by solid phase extraction and LC-MS/MS for THC and its metabolites concentration. In the current study, the highest median THC-COOH and THC-OH concentrations were detected in bile samples (1380 ng/mL and 8 ng/mL, respectively), while the highest THC median concentration was detected in gastric contents (48 ng/mL). This can be explained due to the postmortem distribution of blood to other bodily fluids and tissues and the accumulation in bile following multiple doses. Furthermore, high THC levels in gastric contents can be explained by the undergoing cycles of entero-hepatic circulation which resulted in a significant increase in THC in gastric contents. THC-COOH can be the best indicator to detect cannabinoids in toxicology studies, thus the inclusion of active THC metabolites is essential in death investigations. Additionally, THC-OH concentrations in postmortem cases could be influenced by body mass index. In this study, all types were specimens found to be suitable for testing cannabinoid metabolites, except for vitreous humor which showed low rates of detectability for cannabinoid metabolites. Full article

The IRCGN (Institut de Recherche Criminelle de la Gendarmerie Nationale) is a forensic science institute built by the French Gendarmerie which has the ability to exploit crime scene evidence. Any piece of evidence, anywhere in the world, in any environment, can be examined by IRCGN teams deployed in just a few hours. During the past 10 years, experts specializing in genetics have developed innovative genetic engineering technologies for application in forensic sciences. In this review, we highlight the main innovations and the creation of new tools for human identification, which are fully suited to the French Gendarmerie’s needs. Devices developed by the IRCGN are specific to the Gendarmerie’s purposes. Full article

The practice of latent print analysis is comprised of a visual examination and the comparison of the fingerprint pattern from a questioned print to an exemplar(s). When a questioned print is either smudged or contains little pattern detail, the print comparison would be considered an inconclusive determination. However, in these scenarios, the latent print residues (LPRs) could provide associative information to supplement the current ACE-V (Analysis, Comparison, Examination-Verification) process. Advancements using analytical techniques allow for the analysis of LPR chemistry; however, derivatization is generally required to increase the abundance of components not traditionally observed in gas chromatography. This study aimed to determine whether two derivatization reagents, boron trifluoride in methanol (BF₃-MeOH) and N-methyl-N-(trimethylsilyl)trifluoroacetamide (MSTFA), provide a better recovery of LPR components from a porous or non-porous substrate. Five volunteers deposited groomed latent print samples onto two substrates: a microfiber filter (porous) and a microscope slide (non-porous). The residues were derivatized or evaporated prior to the gas chromatography-mass spectrometry (GC-MS) analysis. The percent recoveries were higher, >83%, in the DCM extracted samples for both substrates compared to those samples prepared in hexanes. DCM/MSTFA derivatization provided the recovery of fatty acids that ranged from 20 to 30% for both substrates and a recovery of squalene at a rate of 2.37% for the filter sample and 4.2% for the slide sample. These rates were higher than the recovery rates obtained for the hexanes/BF₃-MeOH-derivatized samples, with a range of 1–8% for the fatty acids recovery rates and 0.6–0.85% for squalene from both substrates. Overall, the MSTFA derivatization reagent produced higher recoveries for LPR on porous and non-porous substrates while providing a LPR chromatographic profile similar to that of a non-derivatized sample. The use of DCM as a solvent provided a wider range of LPR components recovered than hexanes and, thus, should be used as the extraction solvent when derivatizing samples, regardless of the substrate. Full article

On 19 March 2020, a “state of emergency” was declared in Portugal due to the manifestation of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), with an exponential rate of infection and high mortality and morbidity rates. Since then, the state of emergency was declared a further fifteen times until 30 April 2021, during which a total of 16,974 deaths associated with COVID-19 were acknowledged in the country. Over the aforementioned period, guidelines were followed regarding the handling of suspected cases in autopsy rooms, mortuaries, and cemeteries. However, no procedures have been established regarding the handling of human remains during and after cemeterial exhumations. Furthermore, little is known about the virus survival and its spatial distribution in postmortem human tissues. Given that the minimum Portuguese legal period of inhumation is ending and cemeteries have been facing limited burial space and soon will start exhuming buried individuals, the authors believe it is important to reflect on the matter. Full article

This short communication discusses how a specific geoarchaeological remote-sensing (RS) method, such as analyzing satellite images through NDWI (Normalized Difference Water Index), can be used to aid in searching and locating persons missing in watercourses. Thanks to its high capacity to analyze changes in the surface water area, this index can remotely detect the presence of anomalies related to disappearances in water bodies and provide valuable information that can reduce the use of human resources and help pinpoint likely areas of search. Two real-life cases of missing persons in rivers in which the NDWI index was used are presented, and the results obtained are discussed, emphasizing the importance of NDWI analysis as a complementary method to different approaches, especially non-invasive and remote-sensed ones, when positively searching for missing persons. Full article

Age estimation from developmental traits is typically assessed in isolation, where an age range is derived from known individuals that exhibit that degree of fusion. There are no objective means for incorporating developmental evidence from multiple areas of the skeleton into one cohesive age estimate. This limitation is obvious in the casework at the Defense POW/MIA Accounting Agency (DPAA), where subjectivity is introduced into age estimates based on multiple age indictors. This holds true even when age is derived from one source, The 1957 study by McKern and Stewart). This study uses 388 individuals from the McKern and Stewart study and 41 individuals from the Battle of Tarawa and uses Random Forest Regression (RFR) to estimate an age interval using multiple age indicators. These RFR estimates are compared to age estimates from the Forensic Anthropology Reports (FARs). Overall, FAR age estimates are more accurate (92.7%) than those from the two RFR models (80.5% and 76.6%). This increase in accuracy comes at the cost of some precision (FARs average age interval of 8.1 years and RFR average age intervals of 6.3 and 6.4 years). The RFR models prefer age indicators with late fusion, such as the medial clavicle, and the pubic symphysis, which exhibit a combination of developmental and degenerative ages in morphology. Some avenues for further research are discussed. Full article

Recently, as the interest in cannabidiol (CBD) has grown due to its therapeutic potential, e-cigarette liquids containing CBD have proliferated on the market. Typically, e-liquids contain variable concentrations of CBD (from 2 mg∙mL⁻¹ to 20 mg∙mL⁻¹) in propylene glycol or 70:30 propylene glycol:glycerol mixture and are eventually flavored with food-grade flavors. In this work, carried out by a GC-MS analysis of the condensed smoke produced by a real e-cig, we have demonstrated the actual amount of CBD that can survive the smoking process, and we found that negligible amounts of THCs are formed during the smoking process (i.e., the amount formed was <0.005 mg for each mg of vaped CBD); considering that the threshold dose for ∆⁹-THC is around 2.5 mg (smoked or ingested per os), it is reasonable to conclude that accidental THC intoxication is unlikely, which is a very important issue from a forensic point of view, as in some court cases the use of e-cig liquids containing CBD has been argued as being the source of THC intoxication. Furthermore, all the other cannabinoids considered in this study and potentially derived from CBD thermal degradation have concentrations below the instrumental LOD. Full article

Following a recent death, a human skull was found in a worn physician bag at the decedent’s residence. The bag was labeled with the name “G.B. Ward”, who was found to be a practicing physician and surgeon in the late 1800s, and contained historic medical paraphernalia and letters and receipts dated to the late 1890s. A forensic anthropological analysis of the skull concluded that it was not of modern medicolegal significance but revealed certain inconsistencies with standard professionally prepared anatomical specimens. This initiated further investigation into the history of G.B. Ward, which ultimately resulted in the circumstantial identification of the skull and revealed more than forty detailed newspaper accounts of its evidentiary use in an 1895 homicide trial in the rural United States. Ultimately, the Prosecution’s argument was likely based on the misinterpretation of a transmaxillary (Le Fort) fracture, which had yet to be defined in the medical literature. This case study emphasizes the importance of investigative and forensic anthropological efforts and cautions against cursory designations of skeletal remains as medical specimens. It also highlights the early recognition of the evidentiary value of skeletal remains in court cases and pioneering efforts in performing forensic skeletal trauma analyses. Full article

Novichok-like or fourth-generation agents (FGAs) are chemical warfare agents (CWAs) which have been gaining attention since their use in assassination attempts on Sergei Skripal and Alexei Navalny. Due to their physicochemical properties, these substances are difficult to detect by implemented technologies, resulting in massive response efforts if their occurrence is suspected in a civilian environment. In this work, an approach is presented that uses handheld forensic light sources to visually detect surfaces contaminated with Novichok. More than 100 different wavelength combinations were applied to seven substances chosen to represent the newly listed schedule 1 subgroups in the Annex on Chemicals of the Chemical Weapons Convention. One waveband was identified as promising, which allowed the optical detection of all tested substances. Several surfaces, which could be affected in case of a possible attack using novichok-like nerve agents, were also successfully evaluated. The proposed procedure could be implemented for CBRN responders and security agencies to significantly reduce response efforts, thereby diminishing the overall threat posed by this group of chemicals (FGAs). This procedure was also extended to carbamates and CWAs. Full article

In forensic anthropology, and biological anthropology more broadly, age estimation is a crucial element of the biological profile. The development of osteoarthritis (OA) is correlated with age and, in 2019, Winburn and Stock published a method of estimating age in a sample of 408 white American individuals using OA presence/absence. The current study expanded the original study by testing its accuracy on a more diverse sample, including black, indigenous, and people of color (BIPOC). This served to test whether embodied inequity from lived experiences may preclude the ability of the OA presence/absence method to estimate age at death. This study’s results demonstrated both that the original methodology was validated, and that the approach was accurate at estimating the age of death of BIPOC individuals. Furthermore, this study revealed that the hip and shoulder were highly consistent and reliable and are recommended for use as the strongest indicators of age at death, while the TMJ and ankle performed poorly and should not be used for age estimation. Full article

In forensic genetics, the identification of an individual is often carried out by comparing unknown DNA profiles obtained in a case against databases or references. When no match is found, investigators need new tools in order to obtain additional leads. The latest technical advances now make it possible to predict externally visible characteristics. With this objective, predicting the age of an individual through DNA methylation analysis remains one of the last challenges. The prediction models have to account for the specific constraints of this field, including tissue specificity and DNA availability (i.e., low DNA amounts or low-quality DNA). Jung and colleagues have recently produced models from blood, saliva and buccal cells by using a single base extension sequencing method. With the goal of evaluating these models in our own analytical conditions, saliva and buccal cell samples from 115 French individuals between the ages of 0 and 88 years old were collected and analyzed. After having determined the optimal analysis conditions, including the DNA quantity for bisulfite conversion (75 ng), some differences were highlighted in the measured methylation rates between the two studies. Despite these discrepancies, the prediction performance levels remain very similar, our study showing mean absolute errors of 3.5 years, 3.9 years and 3.2 years, respectively, for the saliva, buccal swab and multitissue model, with limitations observed for the oldest and youngest individuals. Furthermore, we propose the use of a prediction interval with an error dispersion and correct prediction rate at ±5 years and ±10 years, respectively. Full article

Forensic anthropologists build a biological profile—consisting of sex, age, population affinity, and stature estimates—to assist medicolegal stakeholders in the identification of unknown human skeletal remains. While adult age-at-death estimations can narrow the pool of potential individuals, a lack of standards, best practices, and consensus among anthropologists for method selection and the production of a final age estimate present significant challenges. The purpose of this research is to identify age-reporting strategies that provide the most accurate and reliable (i.e., low inaccuracy and low bias) adult age-at-death estimates when evaluated considering the total sample, age cohort (20–39; 40–59; 60–79), and sex. Age-reporting strategies in this study were derived from six age-at-death estimation methods and tested on 58 adult individuals (31 males, 27 females) from the UTK Donated Skeletal Collection. An experienced-based estimation strategy was also assessed. A paired-samples t-test was used to determine whether there was a significant difference (p ≤ 0.05) between the mean estimated age and the actual age for all age-reporting strategies. Results show that the most accurate and reliable age-reporting strategy varied if the sample was evaluated as a whole, by age, or by sex. While none of the age-reporting strategies evaluated in this study were consistently the most accurate and reliable for all of the sample categories, the experience-based approach performed well for each group. Full article

Forensic sciences aggregate a series of scientific and technological domains that aid the judiciary and judicial system. Despite the highly specialized and qualified professionals taking a role in forensic practice, this paradigmatic integration of law, science, and technology often leads them to face significant ethical challenges. Indeed, forensic sciences hold a unique position due to the social and legal implications inherent to forensic expertise. The potential interference with personal rights and freedoms requires the professional practice of the forensic specialist to be guided by alignment with scientific-technical competence under the seal of the highest ethical principles. However, the absence of a specific statutory regulation blurs the performance of the forensic professional and may harm the professional credibility but also the scientific domain as a whole. The existence of ethical pillars is essential to support professional practice, following international recommendations in this regard. Herein, we propose a framework for a code of ethics and conduct that is based on the professional particularities characterizing the forensic practice but also considers the ethical issues that are mandatory to ensure high levels of reliability and credibility of forensic specialists. Full article

Age-at-death estimation is influenced by biological and environmental factors. Physiological stress is intertwined with these factors, yet their impact on senescence and age estimation is unknown. Stature, linear enamel hypoplasia (LEH), and antemortem tooth loss (AMTL) in the Hamann–Todd Osteological Collection (n = 297) are used to understand whether physiological stress is related to age estimation inaccuracy using transition analysis (TA). Considering the low socioeconomic status of individuals in the collection, it was expected that many people experienced moderate to severe physiological stressors throughout their lives. Of the sample, 44.1% had at least one LEH, but analyses found no relationship between LEH incidence and TA error. There was no association between stature and TA error for males or females. However, females with at least one LEH had significantly shorter statures (t = 2.412, p = 0.009), but males did not exhibit the same pattern (t = 1.498, p = 0.068). Further, AMTL frequency and TA error were related (r = 0.276, p < 0.001). A partial correlation controlling for age-at-death yielded a correlation coefficient of 0.024 (p = 0.684), suggesting that this relationship is mostly explained by age-at-death. These data suggest that age estimation methods are not significantly affected by physiological stress in this sample, but further investigations are needed to understand how these variables relate to skeletal aging. Full article

Although there are known limited skeletal traits that can be used to estimate age-at-death, an increasing body of literature is addressing this topic. This is particularly true in journals dedicated to forensic anthropology and past population studies. Research has focused mostly on methodological developments, aiming to update and validate age-at-death methods’ accuracy, with recurrent formulation, reformulation, testing, and re-testing of classical methodological approaches in multiple populational datasets and using novel statistical approaches. This paper explores aging research in adults published over the last century, aiming to portray major research agendas and highlight main institutions and co-authorship networks. A comprehensive dataset of bibliometric data from 1225 publications on age-at-death estimation, published between 1890 and October 2022, was used in the analysis. Major results showed that since the 1990s there has been continuous growth in aging research, predominantly by institutions in the United States. However, in the last 2 decades, research contributions from institutions with a wider geographical location were observed. Moreover, the research terms associated with aging are not limited to bone changes. Rather, dental-related changes are major contributors to aging research. Temporal trends suggested changes in research agendas related to terms and institutional co-authorships which may bring more inclusive and accurate-related method developments. Full article

Historically, serial homicide has been defined in various ways by experts. Recently, there have been renewed efforts to arrive at a consensus definition, yet these efforts have not yet been resolved. At the heart of the controversy appears to be the prioritization of either qualitative definitional features, such as offenders’ intentions and motives, or more observable quantitative features, specifically a minimum threshold of completed murders. The present technical note briefly summarizes this controversy before considering new empirical and theoretical research developments. These developments support a definition that includes a three-victim minimum threshold of forensically linked murderers by the same person(s), occurring in separate events over time, wherein a primary motive is often personal gratification (leisure experience). Full article

While a myriad of effective techniques exist to aid in symphyseal age estimation for those 40 years and younger, few offer similar levels of efficacy for those beyond that threshold. Through the application of a novel technique, this study sought to determine whether a closer inspection of degenerative change may help to improve precision in age estimation for post-epiphyseal adults. Results show that the combination of five distinct areas of interest, plus a correction for density, accurately estimated age 87.75% of the time (averaged amongst four observers [spread: 72–100%]) for a subset of 50 living British females. An adjusted R² value of 0.85, an RSME value of 5.62 years, and a PCC value of 0.92 also confirmed the trialed technique to be a good predictor of age for the entirety of the larger female sample (n = 533). Low inaccuracy (3.86 years) and Bias (0.69 years) further indicate that a continuum-based approach, without pre-set phases or ranges, such as was utilized by this research holds the potential to be at least as effective as the currently available methodologies but with the added advantage of allowing for increased variation at the individual level. Age estimation by linear regression, or by simple addition, yielded estimation envelopes (intervals) of 22–23 and 24 years, respectively, which remain narrow enough to be forensically useful while still wide enough to maximize accuracy in mature adults. Full article

This manuscript aims to introduce the Colección Osteológica Subactual de Santiago (COSS), a documented skeletal collection from Santiago, Chile, consisting of 1635 individuals living in low socioeconomic areas of the capital during the late 19th and early 20th centuries. The origin and current state of this collection, as well as the process by which it came to be housed at the University of Chile, is described. As of today, after long efforts for further documentation and improvements on the physical conditions of the collection, biological sex and age-at-death has been documented through burial records for 1198 individuals. Largely studied by Chilean researchers and students, the COSS collection has enabled a great amount of research, while also serving as part of a thriving scholarly community from different disciplines. Finally, discussion around representativeness, legal status and ethical concerns are addressed, highlighting the specific issues faced when working and studying the COSS collection. Full article

In our experience, university students enrolling in health science and forensic science degrees show difficulty in retaining and integrating basic scientific knowledge learned in their first academic year. Furthermore, in the forensic sciences case, many students have oversimplified and unrealistic expectations as a result of the exposure to crime TV shows, internet blogs, and other social media platforms. Our pedagogical proposal is focused on second-year university students, aiming at promoting effective learning and the integration of scientific knowledge from previous courses, in this particular example, molecular and cell biology and biochemistry, with more advanced forensic courses, such as forensic anthropology and odontology. Teams composed of students and tutors from the teaching staff, with the help of dichotomous keys, are challenged to analyze a crime scene and choose the relevant evidence to further investigate, determine the scientific approach, execute the experimental work, interpret the results and, finally, resolve the case. To assess the pedagogical advantages and the receptivity of this project, a survey is to be carried out among students, and respective statistical analysis is also proposed. Finally, we hope this project outline may be adapted to other subjects, and, therefore, be used to address different pedagogical questions in forensic studies. Full article