Forensic experiments on animal scavenging: A systematic literature review on what we have and what we need

Evaluation of porcine decomposition and total body score (TBS) in a central European temperate forest

The total body score (TBS) is a visual scoring method to scale the succession of decomposition stages. It compares decomposition between cadavers, to connect it with external taphonomic factors and estimate the post-mortem interval. To study decomposition in various climatic environments, pigs are often used as human proxies. Currently, there is one TBS system by Keough et al. (J Forensic Sci. 2017;62:986) for surface-deposited domestic pigs, coming from South Africa. Our study aims to evaluate this method and analyze porcine decomposition in Central Europe to inform forensic research and casework. We conducted an experiment studying six 50 kg pig carcasses in a temperate Swiss forest. Three observers documented decomposition patterns and rated the decomposition stages from photographs based on the porcine TBS model by Keough et al. (J Forensic Sci. 2017;62:986). We documented discrepancies between the carcass decomposition of our specimens and those in the South African study, especially related to the high insect activity in our experiment. Furthermore, we noted factors complicating TBS scoring, including rainfall and scavengers. The agreement between TBS observers from photographs was in the highest agreement category apart from one "substantial agreement" category. Our study is the first in Europe to systematically test the Keough et al. (J Forensic Sci. 2017;62:986) method. The results evidence that regional adaptations are required to be applicable for other environments. We present a modified approach based on experimental observations in a Swiss temperate forest. The identification of regional decomposition patterns and drivers will inform future taphonomy research as well as forensic casework in comparable contexts in Central Europe.

Cat and dog scavenging at indoor forensic scenes: strategies for documentation and detection

Vertebrate scavenging on human remains is occasionally observed at indoor forensic scenes, especially when pets have access to the body and their deceased owners were socially distanced. Pets feeding on corpses have implications for the forensic investigation, e.g. for trauma analysis and the assessment of the cause of death, the estimation of the postmortem interval (PMI), or the recovery of the complete set of remains. Documentation of potential scavenging in forensic practice is tenuous and needs to be improved in order to be able to use the information for future casework. Investigators need to be aware of the alterations pets can cause to human remains and how these affect further analyses. Following a combined literature review for cat and canine scavenging, we present seven new cases from Switzerland with cat and/or dog involvement. We then created a flowchart guide for a systematic collection of data to use at indoor forensic scenes of suspected scavenging. Our literature review revealed the challenge in discriminating between scavenging by domestic cats and dogs, based on the appearance of the lesions alone. Furthermore, the information that is often routinely collected in indoor fatalities with potential scavenging activity is not sufficient to perform this separation. To provide a practical basis for cat and canine scavenging and its differentiation, we summarise strategies and present a flowchart to use in forensic casework of suspected indoor scavenging.