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

Report of forensically relevant insects collected from pig and rabbit remains during two forensic entomology workshops in Eastern Massachusetts

Forensic entomology relies on known geographic ranges and seasonal presence of forensically relevant insects. In the Northeastern United States, there is no information on species in the region in early spring. Two forensic entomology workshops took place in April of 2023 and 2024 in Milton, Massachusetts. During this workshop, practitioners were trained in the appropriate collection and storage techniques prior to a practical experience including the collection of insects from pig and rabbit remains. All insects collected were identified down to family or species level. Across both years, Phormia regina (Meigen) (Diptera: Calliphoridae) was the fly consistently colonizing remains and was the oldest immature larvae in all instances. Calliphora vicina (Robineau-Desvoidy) (Diptera: Calliphoridae), Protophormia terraenovae (Robineau-Desvoidy) (Diptera: Calliphoridae), and Muscina stabulans (Fallén) (Diptera: Muscidae) were additional flies co-colonizing remains with P. regina. Other species were found as adults surrounding the remains that included other necrophagous fly species, beetles, and ants. Variation in insects collected between years likely due to high temperature variation. This documentation of species provides context to forensically related flies expected in Eastern Massachusetts and provides research directives in the region.

How to prove neglect in the context of the post-mortem examination

Understanding the causes, extent, and period of neglect is not only a medical but also a forensic task when it comes to legal investigations. In this study, we evaluated 46 autopsied cases where there was clear evidence of physical neglect during the last period of the deceased's life. The age of the deceased ranged from 21 to 96 years; most of them were female (71.7%). The majority of cases (89.9%) took place in a domestic environment, with partners or relatives providing care. The most frequent post-mortem findings were pressure sores, followed by inflammatory skin changes, and signs of malnutrition and dehydration. Neglect was the cause or co-cause of death in 23% of the cases. More than half of the deceased showed severe contamination of the skin surface by excrement, and in almost 40% of the cases, fly infestation was found. The majority of insects belonged to the group of house flies (Diptera: Muscidae), mainly the common house fly, Musca domestica. By analyzing the entomological evidence, it was possible to prove an insect infestation period of at least several days ante-mortem. Since the period of neglect may be relevant in terms of legal proceedings, the present work demonstrates the particular importance of insect traces in providing this evidence. While prosecution and conviction of caregivers remain challenging, it is all the more essential that entomology and legal medicine collaborate on the analysis of findings of neglect.

Intentional child and adolescent homicides in Milan (Italy): A 30-year interdisciplinary study

This study aims to discuss the forensic and criminological implications of child homicides in the territory of Milan, Italy. The authors present a retrospective study on all the cases of child and adolescent homicides, that were observed at the Institute of Legal Medicine of Milan (Italy) in the last 30 years (from January 1991 to December 2020). A total of 46 child homicides were collected, focusing on the sociological features, by highlighting peculiar cases, risk factors, potential changing social trends, and comparing our cases with the current literature. The analysis revealed a statistically significant relationship (p < 0.05) for male adolescents and indicated that adolescent homicides were more frequently perpetrated in extrafamilial contexts. In contrast, neonaticides and infanticides were mainly committed at home. Furthermore, the Fisher's Exact test revealed that child murders were mainly committed by immigrants in the Milan district after 2005 (p < 0.05). The two main causes of death were due to sharp and firearm injuries. While the relationship between homicide clusters and homicides committed by sharp objects was not significant, adolescent homicides were mainly committed using firearms (p < 0.05). The present study may help to identify risk factors for homicides against child and adolescent. Consequently, policies that identify, prevent, and minimize this extreme violence should be designed to interrupt the vicious circle of such dreadful murderous events. Child and adolescent homicides deserve additional focus and better education for healthcare professionals and further research should be carried out to develop therapeutic and caring strategies.

Geometry of posterior larval spiracles to identify medically and forensically important calliphorids in Thailand

Fly identification is the primary step of analysis in forensic entomology. Although morphology and molecular techniques are considered satisfactory methods, some constraints may arise from a financial or even human point of view. Over the past decade, the geometric morphometric approach has been increasingly advocated for the classification and identification of arthropods. This study explored the method for species identification of 800 third-instar larvae of eight blow fly species of medical and forensic importance: Chrysomya chani Kurahashi, Chrysomya megacephala (Fabricius), Chrysomya (Ceylonomyia) nigripes Aubertin, Chrysomya pinguis (Walker), Chrysomya (Achoetandrus) rufifacies (Macquart), Hemipyrellia ligurriens (Wiedemann), Lucilia cuprina (Wiedemann), and Lucilia porphyrina (Walker). Based on the posterior spiracles geometry, the cross-validation revealed a relatively high percentage of correct classification in most species, ranking from 86% to 100%. The results of this study confirmed that the geometric morphometric (GM) analysis of posterior spiracles might be utilized as a larva identification tool. Therefore, this GM method represents one way of overcoming difficulties with the identification of blow fly larvae and can support further studies of these flies.

Morphological changes of larvae and pupae of Lucilia sericata (Diptera: Calliphoridae) reared at two temperatures and on three food types

Determining the minimum postmortem interval (minPMI) from an entomological perspective relies mainly on development data recorded for various species of flies collected from a crime scene or suspicious death. This study focused on the larval and pupal development of Lucilia sericata (Meigen), with an emphasis on the changes of the external morphology of the puparium and its pupal content throughout the duration of metamorphosis. Colonies of L. sericata were reared on 3 types of swine tissue (skeletal muscle, liver tissue, and heart tissue) at 2 different temperature regimes; 24 ± 1 °C and 30 ± 1 °C. The overall developmental time, larval width and length, and inner and outer pupal morphology changes were observed and recorded. The results show that: (i) temperature significantly influenced overall development time, as well as changes in larval width and length, but this effect was not dependent on tissue type; (ii) larval development duration was longest on heart tissue, and shortest on skeletal muscle for both temperatures; and (iii) pupation was longest for larvae reared on skeletal muscle at 24 ± 1 °C, and on liver tissue at 30 ± 1 °C, while those larvae reared on liver tissue at 24 ± 1 °C and heart tissue at 30 ± 1 °C had the shortest pupation period. A seven-character checklist plus 4 landmark stages were developed comprising the external morphology of the puparium and pupal content changes of L. sericata. In conclusion, the study provides larval and pupal development timetables, as well as checklists and photo guides for pupal character development that may be useful for future postmortem determinations.

A Summary of Concepts, Procedures and Techniques Used by Forensic Entomologists and Proxies

Forensic entomology is a branch of forensic science that incorporates insects as a part of solving crime. Insect-based evidence recovered at a crime scene can be used to estimate the minimum postmortem interval, determine if a carcass/corpse has been relocated, and contribute to the cause and manner of death. The current review summarises the stepwise usage of forensic entomology methods at a crime scene and in the laboratory, including specimen collection and rearing, identification, xenobiotic detection, documentation, and referencing previous research and casework. It also provides three standards for the collection of insects when attending a crime scene. The Gold standard attributes to a forensic entomologist (FE) who is likely to be well-trained attending a scene. The subsequent standards (Silver and Bronze) have been added because the authors believe that this information is currently missing in the literature. The purpose is so that an attending crime scene agent/proxy with some basic knowledge and some simple tools can recover almost all the insect information required by an FE to make the best estimation of the minimum postmortem interval.

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.