Exploring the role of the human microbiome in forensic identification: opportunities and challenges.

Forensic microbiology is rapidly emerging as a novel tool for human identification. The human microbiome, comprising diverse microbial communities including fungi, bacteria, protozoa, and viruses, is unique to each individual, offering a new dimension to forensic investigations. While traditional identification methods primarily rely on DNA profiling and fingerprint analysis, they face limitations when complete DNA or fingerprints profiles are unattainable or degraded. In this context, the microbial signatures of the human skin microbiome present a promising alternative due to their resilience to environmental stresses and individual-specific composition. This review explores the potential of microbiome analysis in forensic human identification, evaluating its applications, advantages, limitations, and future prospects. The uniqueness of an individual's microbial community, particularly the skin microbiota, can provide distinctive biological markers for identification purposes, while technological advancements like 16 S rRNA sequencing and metagenomic shotgun sequencing are enhancing the specificity of microbial identification, enabling detailed analysis of these complex ecological communities. Despite these promising findings, current research has not yet achieved a level of identification probability that could establish microbial analysis as a stand-alone evidence tool. Therefore, it is presently considered ancillary to traditional methods, contributing to a more comprehensive biological profile of individuals.

Plastic bag suffocation and codeine overdose: An unusual case of complex suicide and review of the literature.

The term "planned complex suicide" refers to cases where two or more suicide methods are applied simultaneously. Plastic bag suffocation is a suicidal method commonly combined with self-poisoning by inhalation of volatile compounds or pharmacological substances at poisoning dosage. A 67-year-old woman was found dead on the couch. The head was wrapped in a plastic bag knotted at the front of the neck. No signs of struggle were present on the scene. In the fireplace, there were two blisters of acetaminophen/codeine phosphate tablets. Postmortem examination showed congestion of the face and the neck and pulmonary edema with patchy emphysema. There was no evidence of physical duress. Toxic levels of codeine were detected in the blood. The death was related to a complex suicide involving codeine overdose and asphyxia by plastic bag suffocation. The hypoxic/cardioinhibitory effects of plastic bag suffocation combined to codeine-induced deep reduction of respiratory rate, making the suicide hypothesis the more likely scenario. In order to assess what elements contribute to postmortem diagnosis in complex suicides with plastic bag suffocation, a review of the forensic literature published between 2002 and 2022 was performed. This article emphasizes the complexity of diagnosing deaths involving plastic bag suffocation in suicides, particularly when combined with other methods like inert gas inhalation or drug intake. It underscores the importance of comprehensive toxicological analyses, careful scene examination, and histological studies, not forgetting a thorough comparative analysis of the existing literature, to accurately determine the cause and manner of death in such cases.

An unusual case of a triple suicide pact at the time of the COVID-19 pandemic.

In December 2020, the World Health Organization (WHO) declared SARS-CoV2 a global pandemic. Home confinement, low social contacts, and fear of virus transmission played a major role as risk factors for suicides during the following period. Suicide pacts, in particular, showed a different pattern. A rare case of a triple suicide pact among members of the same family nucleus is presented. The victims were an elderly, severely ill woman and her adult children (a son and daughter), linked by a morbid relationship. The last time the family was seen alive was 40 days before the discovery. All corpses presented decompositional changes. After a full autopsy, the cause of death was determined to be a lethal intake of morphine for the mother and acute blood loss due to self-stabbing at the neck for the siblings. The younger woman was under the effects of a large amount of heparin. Toxicological analysis was positive for opioids and alcohol in both siblings. Suicide pacts have rarely been described during the COVID-19 pandemic. In the few cases reported, the victims were more often relatives than people in a romantic relationship. The involvement of three people is unusual, as is the use of different suicide methods among the victims. In the presented case, the elderly mother's imminent death from terminal cancer, her concern over dying in a nondomestic environment, and the siblings' fear of being alone likely led to the conception of the suicide pact. Social isolation and economic difficulties also played a contributing role.

Estimation of Late Postmortem Interval: Where Do We Stand? A Literature Review.

Estimating time since death can be challenging for forensic experts, and is one of the most challenging activities concerning the forensic world. Various methods have been assessed to calculate the postmortem interval on dead bodies in different stages of decomposition and are currently widely used. Nowadays, the only well-recognized dating technique is carbon-14 radioisotope measurement, whereas other methods have been tested throughout the years involving different disciplines with different and sometimes not univocal results. Today, there is no precise and secure method to precisely determine time since death, and late postmortem interval estimation remains one of the most debated topics in forensic pathology. Many proposed methods have shown promising results, and it is desirable that with further studies some of them might become acknowledged techniques to resolve such a difficult and important challenge. The present review aims at presenting studies about the different techniques that have been tested in order to find a valuable method for estimating time since death for skeletal remains. By providing a comprehensive overview, the purpose of this work is to offer readers new perspectives on postmortem interval estimation and to improve current practice in the management of skeletal remains and decomposed bodies.

Review on forensic importance of myiasis: Focus on medicolegal issues on post-mortem interval estimation and neglect evaluation.

Myiasis is the infestation of live vertebrates by dipterous larvae that feed on living or necrotic tissues, liquid body substances or ingested food and develop in or on the vertebrate body. In both animals and humans, myiasis plays a fundamental role in forensic practice because of its implications in the evaluation of cases of neglect and in the mPMI (minimum post-mortem interval) estimation. The present study aims to provide a review of forensic issues related to myiasis. A retrospective analysis was conducted by exploring major electronic literature databases. Methodological evaluation of each study was performed according to the PRISMA (Preferred Reporting Items for Systematic Review and Meta-Analyses) standards. Sixty-one papers were included in this review. Entomology shows great potentiality in forensic investigations, mostly because of its contributory role in mPMI estimation. Such evaluation, however, requires a careful consideration of the possibility of an ante-mortem myiasis infestation, which could complicate the correct assessment of the mPMI. Hence, forensic pathologists should pay attention to the entomological fauna on a corpse, in both fresh and decomposed bodies. Moreover, in cases with poor nutritional or hygienic conditions, myiasis should be carefully evaluated as an indicator of neglect.

Suicide or Homicide? A Case of Self-Inflicted Triple Gunshot Wound by Double-Barrel Shotgun.

ABSTRACT: Differential diagnosis between suicide and homicide by firearms is still a major challenge in forensic practice, especially when multiple gunshot wounds are present. A case of self-inflicted triple wound by double-barrel shotgun is presented. A 73-year-old White male patient was found dead in a wooden area. According to investigations, he had disappeared from home the day before. The corpse was covered with clothing in a prone position on a gravel road, a short distance from a car with driver-side-door open and keys in the ignition. Next to the body, a 12-gauge double-barrel shotgun was found, with 3 fired cartridges and 1 unused in the left front pocket of the trousers. No signs of struggle were present. Two penetrating wounds in the upper torso were detected by postmortem computer tomography. Autopsy showed 2 near-contact entrance wounds in the pectoral region bilaterally, each associated with exit wounds in the omni lateral hip. Only organs of "delayed incapacitation" were injured. Death was determined to be a suicide. This uncommon case of self-inflicted triple wound by shotgun highlights the importance to integrate proper analysis of the scene with autopsy findings in order to avoid misinterpretation of a suicidal death as a homicide.

Black box of diving accidents: Contribution of forensic underwater experts to three fatal cases.

Diving is a popular activity, largely practiced worldwide. Diving fatalities are not rare events, with drowning being the most common cause of death, followed by cardiac-related natural causes, immersion pulmonary edema and arterial gas embolism. In such cases, positive signs of drowning are not specific, depending also on the time of submersion of corpses. Moreover, drowning can be the terminal event. Over the years, measures to perform appropriate post-mortem examination in cases of diving fatalities were suggested, including the execution of post-mortem CT-scan, the use of a decompression chamber and the adoption of specific autoptic techniques. Although a multidisciplinary approach in forensic investigations concerning diving fatalities is discussed, poor cases focus on how the analysis of diving computer records and equipment can contribute to determining the cause of death. The present study shows how the cooperation between a forensic underwater expert and a forensic pathologist played a crucial role in interpreting radiological findings, guiding the autopsy and confirming/denying circumstantial data emerging from the investigations. Technical analysis of dive computer records and diving equipment is a fundamental step in the definition of the cause of death in diving fatalities. All diving computer data, not only those related to maximum depth and ascent's profile, should be considered in detail, and the immersion graph carefully studied by both the forensic pathologist and the forensic underwater experts. The diving technical data can often play a crucial role in explaining any legal issue related to the circumstances of death, possibly leading the prosecutor to further investigation.

Assessment of Cervical Skeletal Trauma: The Synergistic Contribution of Forensic and Clinical Medicine to a Case of Corpse Concealment.

Fatal neck injuries represent a major challenge in forensic pathology because the anatomical complexity and high variability of neck structures make it often extremely difficult to differentiate true pathological findings from artifacts at autopsy. This topic becomes even more relevant when the forensic pathologist is required to make a pathophysiological evaluation of bone fractures in the absence of soft tissue to support the diagnosis. We report a case of unidentified, stone-covered, skeletonized human remains found within a pit below an abandoned building with bony lesions of the cervical spine and ribs, including a full-thickness fracture of the right lateral mass of the atlas (C1). After a careful study of the fractures was carried out by screening forensic literature and anthropological studies, clinical neurosurgical expertise was called upon to provide a reliable explanation. A rapid and violent twisting of the neck in the opposite direction from the fracture site by an attacker who pinned the victim's torso is the scenario that most likely occurred in our case. This case report shows that the diagnosis of cervical spine injuries in skeletal remains should be the result of a multidisciplinary approach that integrates forensic, anthropological, and clinical expertise.

Accidental Injury or "Shaken Elderly Syndrome"? Insights from a Case Report.

Subdural haemorrhage (SDH) as result of a traumatic brain injury (TBI) is a common cause of death in cases of fatal physical abuse. Since intracranial bleeding is a common finding in elderly due to age-related intracranial changes or increasing prevalence of anticoagulant medication, differential diagnosis between inflicted and non-inflicted head injury is challenging. A case of an elderly woman's death caused by TBI is reported. Autopsy showed multiple polychromatic bruises and a frontoparietal hematoma with bilateral subacute SDH. History excluded paraphysiological or pathological non-traumatic conditions that could justify SDH, while iatrogenic factors only played a contributory role. Since polychromatic bruises distributed on the face, the upper extremities and the chest were consistent with forceful grasping/gripping or repeated blows and SDH can form in absence of impact or by mild/minor blows, SDH was considered the result of repeated physical abuses. Differential diagnosis between traumatic and non-traumatic SDH is still challenging for forensic pathologists. As largely accepted in the pediatric population and occasionally described also in adults, however, violent shaking should be also considered as a possible mechanism of SDH-especially in elderly who do not have any sign of impact to the head.

Tortures alleged by migrants in Italy: compatibility and other medicolegal challenges.

BACKGROUND: Illegal immigration to Europe is a well-known phenomenon whose numbers are being steadily increasing in recent years. Most of the immigrants in Italy come from war zones, and many of them submit an asylum application supported by the complaint to have been victims of persecutory acts in their home countries. MATERIAL AND METHODS: One hundred ninety-six medicolegal reports are analyzed considering the different country of origin, the type of the lesions claimed, tools used, evidenced effects, location of the perpetration of the physical abuses, and the possible motivation of the alleged torture. RESULTS: Greater than 80% of the assessed asylum seekers are over 18-year males coming from African countries. Fifty-eight percent of migrants were tortured or abused in countries of transit, 95% in Libya. Economic, familial, politic, and ethnic reasons prevail in some countries of origin, while tortures or abuses perpetrated in transit countries are mainly linked to forced labor and detention. In the 42.2% of cases, no physical evidence of tortures was detected. The Istanbul Protocol resulted to have been only partly applicable and about 40% of the medicolegal reports are "inconclusive" about the compatibility of physical evidence with the alleged tortures. CONCLUSIONS: The medicolegal and forensic experts involved in torture and ill-treatment cases should seek specific education and training to lower the risks of underestimation and the rate of inconclusive reports. More extensive implementation of the Istanbul Protocol in daily practice should be pursued by the authorities in charge of asylum or protection releasement.

Time Flies-Age Grading of Adult Flies for the Estimation of the Post-Mortem Interval.

The estimation of the minimum time since death is one of the main applications of forensic entomology. This can be done by calculating the age of the immature stage of necrophagous flies developing on the corpse, which is confined to approximately 2-4 weeks, depending on temperature and species of the first colonizing wave of flies. Adding the age of the adult flies developed on the dead body could extend this time frame up to several weeks when the body is in a building or closed premise. However, the techniques for accurately estimating the age of adult flies are still in their beginning stages or not sufficiently validated. Here we review the current state of the art of analysing the aging of flies by evaluating the ovarian development, the amount of pteridine in the eyes, the degree of wing damage, the modification of their cuticular hydrocarbon patterns, and the increasing number of growth layers in the cuticula. New approaches, including the use of age specific molecular profiles based on the levels of gene and protein expression and the application of near infrared spectroscopy, are introduced, and the forensic relevance of these methods is discussed.

The applicability of forensic time since death estimation methods for buried bodies in advanced decomposition stages.

Estimation of the postmortem interval in advanced postmortem stages is a challenging task. Although there are several approaches available for addressing postmortem changes of a (human) body or its environment (ecologically and/or biochemically), most are restricted to specific timeframes and/or individual and environmental conditions. It is well known, for instance, that buried bodies decompose in a remarkably different manner than on the ground surface. However, data on how established methods for PMI estimation perform under these conditions are scarce. It is important to understand whether and how postmortem changes are affected under burial conditions, if corrective factors could be conceived, or if methods have to be excluded for respective cases. We present the first multi-methodological assessment of human postmortem decomposition carried out on buried body donors in Europe, at the Amsterdam Research Initiative for Sub-surface Taphonomy and Anthropology (ARISTA) in the Netherlands. We used a multidisciplinary approach to investigate postmortem changes of morphology, skeletal muscle protein decomposition, presence of insects and other necrophilous animals as well as microbial communities (i.e., microbiomes) from August to November 2018 associated with two complete body exhumations and eight partial exhumations. Our results clearly display the current possibilities and limitations of methods for PMI estimation in buried remains and provide a baseline for future research and application.

Postmortem Otorrhagia in Positional Asphyxia.

Otorrhagia is generally associated with basilar skull fractures or diving accidents. In routine forensic medical practice, an accurate knowledge of the etiology of otorrhagia may have a key role to distinguish between traumatic and atraumatic causes and accidental, homicidal, or suicidal manners. The authors present the case of an unusual cause of atraumatic otorrhagia occurred in an elderly farmer found dead in a barn. He remained entrapped in a narrow tunnel created by some hay bales. The autopsy findings revealed only an intense polyvisceral congestion and subpleural petechiae, with no signs of traumatic injuries and no fractures of skull base or temporal pyramid. The cause of death was determined to be positional asphyxia, and the manner of death was deemed accidental. In fact, the head-down position resulted in diaphragm compression causing respiratory failure in combination with the stasis of the upper venous circle districts. Mechanical and gravitational forces related to upside-down position and increased vascular pressure also caused postmortem otorrhagia. In this case, the death scene investigation and circumstantial information allowed for reconstruction of the unique dynamics of the death. At the death scene, the position of the corpse must be accurately investigated because it can explain some cadaveric findings such as the ear bleeding or other markers of increased cephalic venous pressure like pink teeth, facial and conjunctival petechiae, or Tardieu spots. Therefore, forensic pathologists should consider that ear bleeding in dead bodies is not always the evidence of severe head blunt trauma or diving accidents, but it might be a postmortem phenomenon mostly related to body position.

A field study to evaluate PMI estimation methods for advanced decomposition stages.

Estimating the postmortem interval (PMI) is one of the major tasks and a continuous challenge in forensic pathology. It is often an exclusion process of available methods, which ultimately can lead to an unsatisfactory outcome due to poor reliability. This problem is most acute in the late PMI, when decomposition proceeds and some methods (such as rigor, livor, and algor mortis) are no longer applicable. Several methods, such as forensic entomology, skeletal muscle protein degradation, and the study of body decomposition by application of a morphological scoring, are expected to provide further information; however, all have certain limitations and weaknesses. Availability of a tool-box of methods allows a case-specific selection of the most appropriate one(s), or eventually provides improvements in the overall accuracy and precision of the PMI estimation by merging and combining methods. To investigate practical (field) application, eventual interferences, and/or synergetic effects, as well as the robustness of these methods towards specific influencing factors, a field study was conducted, using eight pig cadavers of different body weights and physical coverage, left to decompose under natural conditions for 16 days. Morphological changes during decomposition were assessed using the total body score (TBS), muscle samples were collected to analyze protein degradation, and insect colonization was evaluated. The results reveal strengths and current limitations of all tested methods, as well as promising synergistic effects, and thus, provide a baseline for targeted future research.

Scared to Death: Emotional Stress Causing Fatal Myocardial Infarction With Nonobstructed Coronary Arteries in Women.

Myocardial infarction with nonobstructed coronary arteries (MINOCA) can be triggered by intense emotions. We report 5 cases of emotional stress-related death where forensic examination attributed myocardial infarction to a coronary spasm, with the ultimate cause of death being arrhythmias in 4 cases and cardiac rupture in the fifth. (Level of Difficulty: Beginner.).

CLEIA of humor vitreous in a case of suicidal insulin overdose.

Insulin overdoses have been mostly described in literature as accidental and suicidal deaths, especially in diabetic patients. The present case study deals with a 68 years old male found dead in his bedroom. The victim worked as health care professional in a rescue team, suffering from depression for several years. At the death scene, two ampoules of soluble insulin were recovered close to the body, one of which was empty. At autopsy, no signs of trauma and no injection marks were found at common sub-cutaneous or intravenous injection sites. No other remarkable findings, but hemorrhagic pulmonary edema along with astrogliosis and neuronal degeneration/necrosis in the subcortical regions and corpus callosum were observed. The blood specimen was inadequate due to hemolysis, since it was not centrifugated soon after sampling. Biochemical analysis was performed on bilateral samples of vitreous humor by using electro-chemiluminescence immunoassay (CLEIA). The insulin concentration was 61.11 mU/L in the right vitreous humor and 74.23 mU/L in the left one; the C-peptide concentration was 0.166 ng/mL in right vitreous and 0.157 ng/mL in the left one. The results are in agreement with levels of insulin and C-peptide detected in previous case studies. Based on these findings the cause of death was determined as suicidal insulin overdoses probably by sublingual administration. This way of self-administration was a diagnosis for exclusion as it has been demonstrated that sublingual human insulin has hypoglycemic effects similar to insulin injected. The case study emphasizes the potential role of vitreous humor as reliable alternative substrate for biochemical analysis compared to post-mortem serum or blood samples in cases of fatal insulin intoxication. Furthermore, the CLEIA is an encouraging analytical method to be considered in such cases, although still not validated to perform quantitative analysis of post-mortem fluids.