Underwater decomposition and forensic entomolgy in Portsmouth, England

Investigation of insect succession on human remains can help to provide an estimate of minimum post-mortem interval (mPMI) during death scene investigations. The use of entomological evidence in these situations can be crucial for helping to provide a timeline for events and providing vital links to other corroborating evidence. Insect succession on land is well studied, however although decomposition of human remains in water is known to differ from that on land, little research has been conducted into how these differences extend to forensic entomology. To date no research covering insect succession on remains decomposing in aquatic habitats, which is vital knowledge for accurately estimating mPMI, has been undertaken in the United Kingdom. In addition, personal observation by forensic entomologists and police personnel suggests that forensic entomology is being underused in an investigative context. Through a mixed methods approach and multi-agency collaboration, this study aims to provide data on insect succession in aquatic habitats in Portsmouth and make recommendations for the collection and storage of entomological evidence from aquatic death scenes. Alongside this, questionnaires and interviews will be used to gather data from a range of professionals who may be present at aquatic death scenes on current practices and levels of awareness of forensic entomology. The results of these questionnaires and interviews will be used to provide targeted information and training where gaps in awareness may exist. To provide the data on insect succession in aquatic environments, field studies are being conducted in which piglet carcasses are being allowed to decompose naturally on land (in a small local wooded area), in fresh water (in a pond located in the same wooded area) and in sea water (suspended from a raft in Langstone Harbour
(Portsmouth, UK)). Species colonisation patterns for each habitat will be discussed. As part of death scene investigations the data from this type of study can provide vital supporting information to narrow down searches, corroborate and support other evidence sources and it can provide additional intelligence to inform investigators.