Forensic Sci., Volume 3, Issue 2 (June 2023) – 13 articles

Age-at-death is one of the most valuable pieces of information in a biological profile, and is an important step in identifying remains. Age-at-death estimation by dental means is performed by forensic odontologists and forensic anthropologists in their daily casework tasks. Both forensic odontologists and forensic anthropologists must be aware of all of the age indicators and of all of the methods that can offer the sufficient scientific robusticity that forensic cases require. Osteological and dental methods of age estimation rely on developmental changes in younger individuals and on degenerative changes in older individuals. Skeletal methods based on developmental changes are highly reliable, while methods based on degenerative or post-formation changes show higher variability. From all skeletal methods, those relying on tooth formation and development are the most accurate to assess an individual’s age. Dental methods of age estimation can be implemented in the skeletal analysis of juvenile and adult remains, representing an additional indicator of age. The aim of this review paper is to provide a practical reference for applying dental age estimation to human remains as a part of skeletal analysis. Full article

Incidental findings (IFs) are unexpected disclosures that do not fall within the aim of a test and have a potential impact on an individual’s life. In the forensic field, IFs can be considered information that is not related to the cause of death, the dynamic of the event, or the scope of the investigation. Questions regarding how forensic professionals should consider, address, and report IFs form the focus of our study. This narrative review was performing following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines with the aim of defining and summarizing evidence about IFs, analyzing their ethical and legal management, and emphasizing the importance of adequate informed consent. The current state of the art regarding IFs has revealed the need for guidelines with the purpose of making the best decisions for the parties involved since the circumstances are extremely delicate, and therefore, forensic geneticists require protection and support. For this reason, elaboration of informed consent, which considers the possibility of making accidental discoveries, could operate as an immediate solution to fill the current gaps. However, the development of clear international recommendations is the best solution to such a complex issue. Full article

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