Extensive study on electrocution at the Bureau of Legal Medicine of Milan (1993-2017): Determination of the current mark with scanning electron microscope/energy-dispersive X-ray analysis on paraffin-embedded samples

Pilot Application of SEM/EDX Analysis on Suspected Cigarette Burns in a Forensic Autopsy Case of Child Abuse

ABSTRACT

Cigarette burn lesions present forensic scenarios that are often difficult to investigate, both from a morphological diagnostic point of view and with regard to the mode of infliction, especially if the victim is unable to speak or has died. Although there may be the suspicion for a lesion to be produced by a lit cigarette, to date one can only rely on the morphological aspects that characterize it, and there is a lack of tools to reach the most evidence-based diagnosis possible. This limitation arose when managing a forensic autopsy case of possible child abuse that resulted in the death of the child, characterized by the presence of 3 suspicious cigarette burn lesions. We therefore decided to perform scanning electron microscopy/energy-dispersive x-ray (SEM/EDX) spectrometry analysis on these lesions and on the cigarette butt found at the crime scene. At the same time, SEM/EDX was applied to the analysis of an unlit cigarette in its entirety (obtained from the same source package as the cigarette butt), a positive control skin sample with an iatrogenic cigarette burn injury, and a negative control skin sample. Among the various compounds highlighted on compositional analysis, only sulfuric anhydride (SO 3 ) and phosphoric anhydride (P 2 O 5 ) showed a highly significant distribution pattern by being found in the autopsy samples, the cigarette butt, the tobacco of the unlit cigarette, and the positive skin control. Considering this, cigarette burns appear to follow Locard's principle as well, and similarly to other lesions, SEM/EDX allowed the diagnosis of cigarette burn lesions, already suspected morphologically, to be corroborated. Therefore, SEM/EDX is confirmed as a helpful tool in forensic pathology investigations.

Advances in forensic diagnosis of electric shock death in the absence of typical electrical marks

Electrical injury is a relatively uncommon but potentially devastating form of multi-system injury with high morbidity and mortality. In common electric injury cases, it is usually difficult to find characteristic changes of electric injury in major organs by using routine histopathological test methods unless there are landmark traces of electric injury, known as electric marks. How to determine electric shock death, especially in the absence of typical electrical marks on the body surface in some cases (which account for about two-thirds of electric injury cases), remains a challenging problem in forensic practice. Our summary shows that many current related studies have focused their efforts to find characteristic histopathological changes in major organs of the body caused by electric injury. Based on the results obtained through comparison of the literature, we find that it may be more urgent and important to find the optimal autopsy or sampling sites in cases with no typical electric marks, knowing that these sites may often reflect the most significant histopathological changes of electric injury, for instance anatomy and sampling of the anterior wrist and the medial malleolus in cases involving the hand-to-foot electric circuit pathway. In this article, we make a summary of advances in identification methods of electric injury, hoping that it could provide some new insights for further research in this field.

A Brief Review of Scanning Electron Microscopy With Energy-Dispersive X-ray Use in Forensic Medicine

Scanning electron microscopy with energy-dispersive x-ray (SEM/EDX) analysis is an investigation whose potential has become increasingly important in the field of forensic research and diagnosis. We present the procedure to perform a well-carried-out SEM/EDX analysis on corpses affected by different types of injuries, such as blunt force trauma, ligature strangulation, electrocution, sharp force trauma, gunshot wounds, and intoxication. After the areas of forensic interest have been macroscopically identified, the sampling can be performed in 2 different ways: apposition of the double-sided graphite tape on the damaged area or performing the excision of a biological sample. In both cases, a proper negative control sample is required. In all cases, SEM/EDX analysis can detect exogenous microtraces consistent with the types of injuries involved. In blunt force trauma, microparticles of different nature deriving from the contact of the blunt instrument with the victim may be observed; in sharp force trauma, metal microtraces (Fe, Cr, Al, Ti) can be identified. In ligature strangulation, exogenous microtraces may be found in the cutaneous furrow. In electrocution, it allows to identify the pathognomonic metal pattern (Cu, Zn, Fe) of the "electric mark." In gunshot wounds, the main applications regards the detection of metal particles (Pb, Ba, Sb) of gunshot residues. Finally, in the analysis of intoxicants, it may identify traces of toxic substances. Thus, the authors conclude that SEM/EDX analysis can provide essential information to assist in the medicolegal investigation of death.

Look before washing and cleaning: A caveat to pathologists and anthropologists

Partially or totally skeletonized bodies are undoubtedly the most challenging scenario to deal with for forensic pathologists and anthropologists. Indeed, in such cases, being able to figure out the cause and manner of death is often tricky. Human remains require to be washed and cleaned before a thorough assessment of any signs of trauma. However, bones and any fragment of more or less putrefied soft tissues may be home to crucial traces for investigative purposes. They are often located in the context of apparently meaningless dirt and, sometimes they are even invisible to the naked eye. Therefore, their careless cleaning inevitably leads to an unintentional loss of such traces with a negative impact on subsequent investigations. For these reasons before proceeding with cleaning, exhaustive examination and sampling must be carried out. In particular fragments of soft tissues, even if putrefied, are absolutely not to be considered as a hindrance for forensic purposes, since they could still provide valuable information after histological examination. Finally, forward-thinking professionals should think about the possible presence of exogenous micro-traces of forensic concern and collect specimens to be analyzed through in-depth analyses, such as Scanning Electron Microscopy with Energy Dispersive X-ray Spectrometry (SEM/EDX). The present series of cases demonstrates that crucial forensic information can be obtained through the analysis of apparently meaningless residues and even of micro-traces not visible to the naked eye and mixed with trivial dirt.

Determination of metallization with energy-dispersive X-ray fluorescent spectrometry in experimental electric injury

We investigated the application of energy-dispersive X-ray fluorescent spectrometry (EDX) analysis to the detection of aluminum (Al), tin (Sn) and zinc (Zn) as the electric conductor in experimental electrical injury. Experimental electrical injury was caused by exposure to alternating current at 100 V for 10 s. The peaks of Al, Sn, and Zn were detected by EDX in formalin-fixed skin samples of each current exposure group. Histological examination revealed blister formation in all samples of each current exposure group. EDX analysis technique can be applied to detect Al, Sn, and Zn as the electric conductor, and is useful in the diagnosis of electrocution.

A Pilot Study on the Diagnosis of Fatal Electrocution by the Detection of Myocardial Microhemorrhages

In electrocutions, death may be caused by alterations in the heart conduction system provoking ventricular fibrillation. This study aims to identify histological cardiac markers of high- and low-voltage electrocution. Two groups of decedents were evaluated: group A included 14 fatalities caused by high- or low-voltage electrocution and group B (control) included 14 fatalities due to other traumatic or disease causes. Myocardial sampling with microscopic examination was performed on all the hearts using the hematoxylin and eosin and Masson's trichrome stains to investigate morphological characteristics that could indicate the damage caused by high- and low-voltage electrocutions. Interstitial myocardial hemorrhagic infiltration was the only differentiating finding, which was shown only in high-voltage electrocution. This pathological finding has not been previously reported, and it may be specific to high-voltage electrocution deaths. Further studies are warranted.