Automatic detection and identification of diatoms in complex background for suspected drowning cases through object detection models.

The diagnosis of drowning is one of the most difficult tasks in forensic medicine. The diatom test is a complementary analysis method that may help the forensic pathologist in the diagnosis of drowning and the localization of the drowning site. This test consists in detecting or identifying diatoms, unicellular algae, in tissue and water samples. In order to observe diatoms under light microscopy, those samples may be digested by enzymes such as proteinase K. However, this digestion method may leave high amounts of debris, leading thus to a difficult detection and identification of diatoms. To the best of our knowledge, no model is proved to detect and identify accurately diatom species observed in highly complex backgrounds under light microscopy. Therefore, a novel method of model development for diatom detection and identification in a forensic context, based on sequential transfer learning of object detection models, is proposed in this article. The best resulting models are able to detect and identify up to 50 species of forensically relevant diatoms with an average precision and an average recall ranging from 0.7 to 1 depending on the concerned species. The models were developed by sequential transfer learning and globally outperformed those developed by traditional transfer learning. The best model of diatom species identification is expected to be used in routine at the Medicolegal Institute of Paris.

Artificial intelligence in the practice of forensic medicine: a scoping review.

Forensic medicine is a thriving application field for artificial intelligence (AI). Indeed, AI applications intended to forensic pathologists or forensic physicians have emerged since the last decade. For example, AI models were developed to help estimate the biological age of migrants or human remains. However, the uses of AI applications by forensic pathologists or physicians and their levels of integration in medicolegal practices are not well described yet. Therefore, a scoping review was conducted on PubMed, ScienceDirect, and Scopus databases. This review included articles that mention any AI application used by forensic pathologists or physicians in practice or any AI model applied in one expertise field of the forensic pathologist or physician. Articles in other languages than English or French or dealing mainly with complementary analyses handled by experts who are not forensic pathologists or physicians or with AI to analyze data for research purposes in forensic medicine were excluded from this review. All the relevant information was retrieved in each article from a grid analysis derived and adapted from the TRIPOD checklist. This review included 35 articles and revealed that AI applications are developed in thanatology and in clinical forensic medicine. However, those applications seem to mainly remain in research and development stages. Indeed, the use of AI applications by forensic pathologists or physicians is not actual due to issues discussed in this article. Finally, the integration of AI in daily medicolegal practice involves not only forensic pathologists or physicians but also legal professionals.

CT analysis of skull contents in naturally mummified human corpses, a multicentric study.

INTRODUCTION: This study aimed to assess skull contents, brain appearance, and density on postmortem computed tomography in naturally mummified corpses. MATERIAL AND METHODS: For this purpose, a retrospective multicentric study, including mummified corpses from two French centers (Brest and Nantes) and from the New Mexico Decedent Image Database (USA), was performed by analyzing postmortem computed tomography (PMCT) focused on the head and neck of partially or fully mummified corpses discovered between 2011 and 2022. The PMCT analysis provided data on the CT appearance of brains, allowing them to be classified into four different categories (desiccation, liquefaction, dura mater only (DMO), and absence), and to measure densities (HU) of the brain remains. In addition, data on postmortem intervals (PMI) from Nantes and Brest centers were collected and analyzed to test the link between brain densities and PMIs. RESULTS: 54 cases of naturally mummified corpses were included. The brains were classified as liquefied (56%), desiccated (17 %), DMO (20 %), and absent (7 %) based on their CT appearance. Dehydrated brains were significantly (p < 0.004) denser (median 102 HU, interquartile range (IQR) 41) than either liquefied brains (median 39.5 HU, IQR 9) or brains with DMO (median -25 HU, IQR 57). However, the density of brain remains was not significantly affected by where the bodies were found (p = 0,41). Analysis of PMI and brain densities was performed on 22 cases. The results showed that brain remains were significantly (p = 0.039) denser when they were found after a PMI of more than six months. CONCLUSION: Brain desiccation was the aspect with the highest densities on PMCT, and for which we were able to highlight great preservation of anatomical structures observable in living organisms.

Validation of a post-mortem computed tomography method for age estimation based on the 4th rib in a French population.

Age estimation is a key factor for identification procedure in forensic context. Based on anthropological findings, degenerative changes of the sternal extremity of the 4th rib are currently used for age estimation. These have been adapted to post-mortem computed tomography (PMCT). The aim of this study was to validate a post-mortem computed tomography method based on a revision of the Iscan's method on a French sample. A total of 250 PMCT (aged from 18-98 years (IQR 36-68 years, median 51 years); 68 (27%) females) from the Medicolegal Institute of Paris (MLIP) were analyzed by two radiologists. The sternal extremity of 4th right rib was scored using method adapted from Iscan et al. Weighted κ was used to evaluate intra- and inter-observer reliability and Spearman correlation was performed to evaluate relationship between age and score. Confidence intervals for individual prediction of age based on 4th rib score and sex were computed with bootstrapping. The intra-observer reliability and inter-observer reliability were almost perfect (weighted κ = 0.85 [95%CI: 0.78-0.93] and 0.82 [95%CI 0.70-0.96] respectively). We confirmed a high correlation between the 4th rib score and subject age (rho = 0.72, p < 0.001), although the confidence intervals for individual age prediction were large, spanning over several decades. This study confirms the high reliability of Iscan method applied to PMCT for age estimation, although future multimodal age prediction techniques may help reducing the span of confidence intervals for individual age estimation.Trial registration: INDS 0,509,211,020, October 2020, retrospectively registered.

Forensic answers to the 14th of July 2016 terrorist attack in Nice.

The terrorist attack of July 14, 2016 in Nice (France) was a devastating event. A man voluntarily drove a truck into a crowd gathered for the fireworks display on the seaside "Promenade des Anglais," plowing pedestrians down over more than 2 km before being shot dead. At the time of this report, a total of 86 casualties and more than 1200 formal complaints for physical and psychological injuries have been recorded. The aim of this work is to describe the forensic management of this event and its immediate aftermath. This paper reaffirms the basic tenets of disaster management: a single place of work, teamwork in times of crisis, a single communication channel with families and the media, and the validation of the identifications by a multidisciplinary commission. This paper highlights other essential aspects of the organization of the forensic effort put in place after the Nice attack: the contribution of the police at the crime scene, the cooperation between the disaster victim identification (DVI) team, and the forensic pathologists at the morgue, applying the identification (ID) process to unconscious victims in the intensive care unit, the input of volunteers, and the logistics associated with the management of the aftermath of the event. All of the victims were positively identified within 4 and a half days. For the first time in such a paper, the central role of medical students in the immediate aftermath of the disaster is outlined. The need to address the possible psychological trauma of the non-medical and even the medical staff taking part in the forensic effort is also reaffirmed.

Terrorist explosive belt attacks: specific patterns of bone traumas.

In cases of terrorist bomb attacks, the issue of victim identification is the principal aim. For investigators and justice, terrorists must also be identified in a timely manner. The fragmentation of bodies caused by explosive devices however makes this operation difficult. The cases presented correspond to six autopsies of perpetrators carrying explosives. Their explosive belts produced different body sections on areas correlated with the location on the body of carrying explosive charges. Indeed, cross-sectional areas are the signature of the level of explosive devices on the body, and some fracture features through the damage of certain areas of constitutional weaknesses are specific elements to consider. These elements can allow a quick distinction between victims and terrorists, in order to assist in the medico-legal process of identification.

Bone and soft tissue histology: a new approach to determine characteristics of offending instrument in sharp force injuries.

This paper describes a new approach to determine characteristics of the implement used to inflict trauma which involves the histological analysis of exogenous particles. Based on Locard's principle "every contact leaves a trace," we decided to assess whether histological examination of bone and soft tissue around a penetrating injury (sharp force trauma) could provide evidence of the offending implement. Case reports and experimental studies have demonstrated the potential of cut mark features in bone to identify the causative implement and potentially assist in identifying the perpetrator. Scanning electron microscopy in combination with energy-dispersive X-ray spectrometry (SEM/EDS) have previously been reported to identify exogenous particles from various implements. In medical research, histological techniques are used to study the impact of foreign particles in tissues originating from implants. However, the routine use of histology in forensic medicine focuses on understanding type and timing of injuries. Based on three forensic cases, the results presented in this paper demonstrate that histology offers a cost-efficient and reliable means to detect foreign particles related to offending implement and/or to the environment where the victim was located. The interpretation of histological results was performed in conjunction with the macroscopic autopsy findings and anthropological analysis of bone samples.

An evaluation of the differences in paediatric skeletal trauma between fatal simple short falls and physical abuse blunt impact loads: An international multicentre pilot study.

In cases where a deceased child exhibits trauma as a result of a physical abuse blunt impact load, a parent/caregiver may provide a simple short fall (SSF) as the justification for that trauma. The skeletal fractures remain difficult to differentiate between a SSF and physical abuse however, as both are the result of a blunt impact load, and are therefore biomechanically alike, and the rare nature of these fatalities means only anecdotal research has been available to validate such claims. The aim of this pilot study was to investigate if there may be differences in the skeletal fracture patterns and types resulting from SSFs compared with those resulting from physical abuse blunt impacts. Paediatric (<10 years) cases of fatal SSFs (≤1.5 m) and physical abuse were collected from the Victorian Institute of Forensic Medicine (Australia), Institut Médico-Légal de Paris (France), University of Pretoria (South Africa) and Great Ormond Street Hospital (England). For each case the intrinsic and extrinsic variables were recorded from medico-legal reports and skeletal trauma was documented using post-mortem computed tomography scans and/or skeletal surveys. Three SSFs and 18 physical abuse cases were identified. Of the SSF cases, two exhibited fractures; both of which were simple linear neurocranial fractures. Comparatively, 12 of the physical abuse cases exhibited fractures and these were distributed across the skeleton; 58% located only in the skull, 17% only in the post-cranial and 25% located in both. Skull fracture types were single linear, multiple linear and comminuted. This pilot study suggests, anecdotally, there may be differences in the fracture patterns and types between blunt impact loads resulting from a SSF and physical abuse. This data will form the foundation of the Registry of Paediatric Fatal Fractures (RPFF) which, with further multicentre contributions, would allow this finding to be validated.

Disaster victim identification operations with fragmented, burnt, or commingled remains: experience-based recommendations.

Human-made and natural disasters can result in severely fragmented, compromised, and commingled human remains. The related disaster victim identification (DVI) operations are invariably challenging, with the state of the remains potentially precluding some identifications. Practitioners involved in these DVI operations will routinely face logistical, practical, and ethical challenges. This review provides information and guidance derived from first-hand experiences to individuals tasked with managing DVI operations with fragmented human remains. We outline several key issues that should be addressed during disaster preparedness planning and at the outset of an operation, when incident-specific strategies are developed. Specific challenges during recovery and examination of fragmented remains are addressed, highlighting the importance of experienced specialists at the scene and in the mortuary. DNA sample selection and sampling techniques are reviewed, as well as downstream effects of commingling and contamination, which can complicate reconciliation and emphasise the need for rigorous quality control. We also touch on issues that may arise during communication with families. While recommendations are provided, they are not intended as proscriptive policy but rather as an addition to the general recommendations given in the International Criminal Police Organization (INTERPOL) DVI Guide, to inform preparative discussions between government officials, judiciary, police, and forensic specialists.Key pointsA DVI operation for an incident characterised by many fragmented and otherwise compromised human remains poses specific challenges that may prolong and complicate identifications.Specialists should be consulted at the outset to address key issues related to the aim and extent of the operation.Specialist expertise in handling compromised human remains is indispensable at the scene, in the mortuary, during reconciliation, and for quality control.Continuous consultation between representatives from government, the judiciary, law enforcement, the media, and various forensic specialists will prevent unnecessary delay and facilitate accurate and timely communication.

Terrorist attacks: cutaneous patterns of gunshot and secondary blast injuries.

Terrorist attacks have been on the rise. During the recent terrorist attacks in France, terrorists perpetrated their acts using weapons of war, as well as explosive charges. These two modes of action, when combined, can create skin lesions with similar macroscopic appearances, which can sometimes go unnoticed because of body fragmentation. A total of 68 autopsies, 83 external examinations, 140 standard radiographic examinations, and 49 computed tomography (CT) scans were performed over 7 days during the 2015 terrorist attacks in France. Bodies were injured by firearms and shrapnel-like projectiles. We analysed the clinical findings for the secondary blast cutaneous lesions from the explosive devices and compared these lesions with ballistic-related lesions to highlight that patterns can be macroscopically similar on external examination. Secondary blast injuries are characterised by penetrating trauma associated with materials added to explosive systems that are propelled by explosive air movement. These injuries are caused most often by small, shrapnel-like metallic objects, such as nails and bolts. Propulsion causes ballistic-type injuries that must be recognised and distinguished from those caused by firearm projectiles. Differentiating between these lesions is very difficult when using conventional criteria (size, shape, number and distribution on the body) with only external examination of corpses. This is why the particularities of these lesions must be further illustrated and then confirmed by complete autopsies and radiological and anatomopathological examinations.Key pointsWhen occurring simultaneously in terrorist attacks, injuries caused by secondary blasts appear as cutaneous wound patterns that can be macroscopically very similar to those caused by firearm projectiles.The criteria usually found in the literature for distinguishing these two types of projectiles may be difficult to use.It is important in these difficult situations to benefit from systematic postmortem imaging.Systematic autopsy and then anatomopathological analyses of the orifices also help determine the cause of the wounds.

An overview of forensic operations performed following the terrorist attacks on November 13, 2015, in Paris.

On the evening of November 13, 2015, the city of Paris and its surroundings was hit by a series of attacks committed by terrorist groups, using firearms and explosives. The final toll was 140 people deceased (130 victims and 10 terrorists or their relatives) and more than 413 injured, making these attacks the worst mass killings ever recorded in Paris in peacetime. This article presents the forensic operations carried out at the Medicolegal Institute of Paris (MLIP) following these attacks. A total of 68 autopsies of bodies or body fragments and 83 external examinations were performed within 7 days, and the overall forensic operations (including formal identification of the latest victims) were completed 10 days after the attacks. Over this period, 156 body presentations (some bodies were presented several times) were provided to families or relatives. Regarding the 130 civilian casualties, 129 died from firearm wounds and one died from blast injuries after an explosion. Of the 10 terrorists or their relatives who were killed, eight died from suicide bombing, one was shot by police and one died from crush injuries due to partial collapse of a building following the police raid against a terrorist's hideout after the attacks. All mass shootings were perpetrated with AK-47 or Zastava M70 assault rifles using 7.62 mm × 39 mm cartridges. In the case of ballistic injuries, death was most often obviously caused by craniocerebral injuries, extensive organ lacerations and/or massive haemorrhage. Among the terrorists killed by bombing, the lesion patterns were body transection, multiple amputations, extreme organ lacerations and the presence of foreign bodies owing to the shrapnel load (steel nuts, glass fragments) or the explosive charge fastening system of the devices. This discussion highlights the particular difficulties of interpretation encountered within the framework of ballistic injuries, a conclusion that should lead to a modest and realistic approach in these exceptional situations where forensic operations involve a very large number of victims in a constrained time.

The petrous bone: Ideal substrate in legal medicine?

Over the last few years, palaeogenomic studies of the petrous bone (the densest part of the temporal bone) have shown that it is a source of DNA in both larger quantities and of better quality than other bones. This dense bone around the otic capsule has therefore been called the choice substrate in palaeogenomics. Because the practice of forensic genetics responds to different imperatives, we implemented a study aimed at (i) understanding how and why the petrous bone is an advantageous substrate in ancient DNA studies and (ii) establishing whether it is advantageous in forensic STR typing. We selected 50 individual skeletal remains and extracted DNA from one tooth and one petrous bone from each. We then amplified 24 STR markers commonly used in forensic identification and compared the quality of that amplification using the RFU intensities of the signal as read on the STR profiles. We also performed histological analyses to compare (i) the microscopic structure of a petrous bone and of a tooth and (ii) the microscopic structure of fresh petrous bone and of an archaeological or forensic sample. We show that the RFU intensities read on STR profiles are systematically higher in experiments using DNA extracted from petrous bones rather than teeth. For this reason, we were more likely to obtain a complete STR profile from petrous bone material, increasing the chance of identification in a forensic setting. Histological analyses revealed peculiar microstructural characteristics (tissue organization), unique to the petrous bone, that might explain the good preservation of DNA in that substrate. Therefore, it appears that despite the necessity of analysing longer fragments in forensic STR typing compared to NGS palaeogenomics, the use of petrous bones in forensic genetics could prove valuable, especially in cases involving infants, toothless individuals or very degraded skeletal remains.

The role of forensic anthropology in disaster victim identification (DVI): recent developments and future prospects.

Forensic anthropological knowledge has been used in disaster victim identification (DVI) for over a century, but over the past decades, there have been a number of disaster events which have seen an increasing role for the forensic anthropologist. The experiences gained from some of the latest DVI operations have provided valuable lessons that have had an effect on the role and perceived value of the forensic anthropologist as part of the team managing the DVI process. This paper provides an overview of the ways in which forensic anthropologists may contribute to DVI with emphasis on how recent experiences and developments in forensic anthropology have augmented these contributions. Consequently, this paper reviews the value of forensic anthropological expertise at the disaster scene and in the mortuary, and discusses the way in which forensic anthropologists may use imaging in DVI efforts. Tissue-sampling strategies for DNA analysis, especially in the case of disasters with a large amount of fragmented remains, are also discussed. Additionally, consideration is given to the identification of survivors; the statistical basis of identification; the challenges related to some specific disaster scenarios; and education and training. Although forensic anthropologists can play a valuable role in different phases of a DVI operation, they never practice in isolation. The DVI process requires a multidisciplinary approach and, therefore, has a close collaboration with a range of forensic specialists.

The potential of forensic analysis on human bones found in riverine environment.

Human remains found in aquatic contexts are frequently recovered incomplete and badly decomposed, and therefore present a challenge for medico-legal institutes as their possibilities of analysis for identification and investigation of cause and manner of death are limited. This article aims to demonstrate the potential of forensic examination and analyses (DNA, toxicology, diatoms and entomology) on a set of bones recovered from a river in Strasbourg and the possibility to trigger identification of the victim and circumstances of death despite the state of decomposition and incompleteness of remains.

Missing in Amazonian jungle: a case report of skeletal evidence for dismemberment.

This case study presents the results of the recovery and analysis of three sets of disarticulated and incomplete human remains found in Ecuador, within the Amazonian jungle. Recovered body parts sustained extensive sharp force trauma situated on different aspect of the skeleton. The anthropological examination (bone reassembly, biological profile) was followed by a detailed analysis of cut marks, including a basic experimental study on pig bones to demonstrate that dismemberment may have occurred within a certain amount of time after death. Despite the location (deep into the Amazonian jungle) and the perpetrator's actions (dismemberment and dispersion of body parts in a river), forensic work both on the field and in laboratory allowed identification of the victims and the reconstruction of the sequence of events.