Paola A. Magni OSI

Learning Overview: The goal of this paper is to present the multidisciplinary investigation performed on a unknown corpse found in water. The corpse was in advanced state of decomposition and the study of barnacles led to the estimation of the Postmortem Interval (PMI). Impact Statement: This presentation will impact the forensic community by informing attendees of the importance of a multidisciplinary forensic approach and the use of barnacles for PMI estimation. Human remains can be found in water environments for multiple reasons such as accident, natural or mass disasters, homicide, and suicide. The characteristics of aquatic environments are many and varied and all unique in terms of biological, chemical, and physical properties. The decomposition process and the colonization of the remains are strictly related to these characteristics. As any other forensic medical investigation, when a corpse is recovered from an aquatic environment, primary tasks are the confirmation of the personal identification, the determination of the cause of death, and the estimation of the time since death (PMI). To date, considering the difficulties in the evaluation of postmortem changes, several studies have suggested the use of aquatic organisms, such as macroinvertebrates and algae in both freshwater and saltwater environments, to aid in the estimation of the PMI. In particular, for cases that occurred in seawater, the analyses of the barnacles (Crustacea: Cirripedia) colonizing the remains and the clothes and the objects associated with it have proven to be able to provide important information both on the provenance of the corpse and the PMI. The present casework reports the multidisciplinary investigation performed on a corpse recovered in the Strait of Sicily in the Mediterranean Sea. The corpse was found in an advanced stage of decay, partially skeletonized and dismembered, with diffuse adipocere. Goose barnacles (Lepas anatifera L.; Crustacea: Cirripedia: Pedunculata) were found colonizing the items connected with the corpse (a watch, a single sock, and a shoe), the teeth, the exposed bones, and, for the first time, were also observed attached directly on the corpse’s skin. A complete medicolegal investigation comprehensive consisting of a Computed Tomography (CT) scan and diatom-test allowed ascertainment of the cause of death by drowning, while the use of barnacles and oceanographical data were used to estimate the floating time and the journey traveled by the corpse. The DNA profile of the subject was uploaded in the official international databank; however, at present the identity of the subject remains unknown. Despite this case being still open, the multidisciplinary approach to this complex investigation should be used as a guideline for future similar cases.

Learning Overview: After attending this presentation, attendees will have a better understanding of the impact and the artifacts produced by the activity of necrophagous entomofauna on stab-cuts and tear damage on different types of fabric during the postmortem period. Impact Statement: This presentation will impact the forensic science community by increasing awareness of the effect of carrion insects on clothing and by providing a new body of information that will enhance the investigative role of clothing associated with decomposed and skeletonized remains. Fatal stabbing incidents are the leading cause of homicides in countries with restricted access to firearms, such as Australia.1 During a stabbing assault, the distinctive characteristics of a sharp implement will deposit specific features.2 When the decomposition process impedes the physical examination of a stab wound, damage analysis of the clothing may provide information about the weapon or the actions that caused the injury.3 Studies have suggested that insect activity associated with decomposition can produce artifacts on textiles, modify perimortem textile damage or produce changes to clothing that imitate indicators of sexual homicides.4-7 However, the extent of such studies is currently limited and have not been conducted in Australia before. The aim of this research was to identify and characterize the effect of carrion insects on textile damage after a decomposition period during summer in Australia. The effect of insect activity was analyzed on standardized cuts and tears to three different fabrics (100% cotton, 65% polyester-35% cotton, 80% nylon- 20% spandex). Ninety stillborn piglets (Sus scrofa domesticus L.) were wrapped in one type of fabric each. Each clothed piglet was either stabbed by a stabbing apparatus or had its fabric torn. All piglets were placed simultaneously in a decomposition facility alongside controls of each combination of fabric and damage type, including 9 piglets clothed and intact; 6 piglets unclothed and stabbed or intact; 11 piglets enclosed in boxes; 36 field swatches; and 9 laboratory swatches. Over five sampling periods and until complete skeletonization (7, 12, 18, 26, 47 days since placement), 3 piglets of each type were removed, and entomological samples were collected. The fabric of each piglet was removed, photographed, and stored to dry in laboratory conditions before being analyzed. All controls and fabric swatches were collected on the final sampling day. Data collection was comprehensive of piglet and fabric samples via field assessment, daily photo and video documentation, static camera recording, and direct collection of insect specimens. Analyses performed covered taphonomic aspects (degree of piglet decomposition), entomological (insect species and instar), and textile damage analysis. The collected fabrics were analyzed on different levels of fabric structure using a stereoscope and digital microscope and through photo and video analysis. Fibers of each sample type were collected and examined using optical microscopy and Scanning Electron Microscopy (SEM). The results of this research show that stab cuts can adopt morphological characteristics over time that may resemble features of tear damage, whereas tear characteristics also tend to fade gradually. Insect interaction with bloodstains resulted in a distortion of the yarns and of the fabric surface after fly feeding. Due to the weakening of the fabric’s structure, insect damage and consequent degradation may occur at the same location. The assessment and comparison of fabrics revealed how parameters such as the type of fabric and elasticity can influence insect damage, with natural fabrics being the most vulnerable. Lastly, this research emphasizes how the presence and the type of fabrics and textile damage affect the interaction of carrion insects with the decomposing medium, and consequently, how the rate of decomposition in a natural environment and in confined spaces is affected.

Learning Overview: After attending this presentation, attendees will understand the effect of carrion insects on fabrics during the postmortem period. In particular, attendees will understand those variables (e.g., the nature of the fabric [natural, synthetic, blended], the fabric’s elastic content [% in elastane], the type of initial damage [tear/penetration] that will most impact on how the fabric modifies during a decomposition event). Impact on the Forensic Science Community: This presentation will impact the forensic science community by providing a new body of information that will enhance the investigative role of clothing associated with decomposed and skeletonized remains. Fatal stabbing incidents are the leading cause of homicides predominantly in countries with restricted access to firearms, such as Australia. During a stabbing assault, the distinctive characteristics of an implement deposit specific features, typically assessed during wound examination by a pathologist and/or during a fabric damage assessment by a forensic scientist. When the decomposition process impedes the identification and evaluation of the type and extent of a stabbing wound, fabric damage analysis on the victim’s clothing may provide information about the implement or the actions that caused the injuries. However, studies have suggested that insect activity can modify the original cut (e.g., exacerbating the fraying of a fabric’s cut, especially the edges of the cut). Furthermore, insect activity and the progression of decomposition such as bloating have also been reported to produce changes to clothing that in some cases may mimic indicators of sexual homicides. At present, there is a paucity of research focused on the effect of insect activity on different fabrics and the modifications they cause throughout the process of decomposition. The aim of this study is to analyze the effects of the activity of the necrophagous entomofauna during a summer season in Western Australia on different types of fabric (natural, synthetic, blended—with different amount of elastin), type of damage (tear/penetration), and time since death/insect colonization. For this study, 117 piglets (Sus scrofa L.) were used. Four different fabrics were selected based on their type (natural/synthetic) and their percentage in elastin (0%, 50%, 100%): (1) cotton 100%; (2) polyester 100%; (3) cotton-elastane 50%–50%; and (4) spandex 100%. All fabrics were woven. Of the 117 piglets, 112 were wrapped from the neck down with one layer of each fabric type and in the same weave orientation. Five piglets were not clothed and were used as controls. Twenty-four wrapped piglets were stabbed twice, consecutively and at identical anatomical positions with a Philips-head screwdriver (pointed edge) and 24 with a kitchen knife (sharp edge) by utilizing a stabbing apparatus (for consistency and to maintain a similar amount of pressure when thrusting). The fabric of 24 wrapped piglets was torn twice at the same positions as the penetrated piglets. Twenty-four wrapped piglets were left undamaged and 17 wrapped piglets were excluded from insect activity to serve as controls. Also, 112 samples of fabrics that were not wrapped on piglets were placed at the field site along with the samples. The experiment took place in a eucalypt woodland on sandy soil in southwestern Australia. The environmental conditions were also documented. Data collection was comprehensive of piglets, fabrics sample (a total of 20 replicants every three days from the beginning of the experiment), and insect specimens (via direct collection and adhesive traps). At each sampling period, photos and videos were recorded. Analyses performed covered both taphonomic aspects (degree of piglets’ decomposition), entomological (insect species and instar), and physical evidence (fabric damage via stereomicroscope and Scanning Electron Microscopy [SEM]). The statistical analysis considered the different variables (e.g., time since death, insect activity, type of fabric, type of damage) and assisted in the generation of likelihood ratios for the interpretation of damage on the fabrics. This presentation will discuss the results of this experiment and its impact on postmortem interval assessments, as well as implications on fabric damage analysis.