To Be There or Not to Be There, That Is the Question-On the Problem of Delayed Sampling of Entomological Evidence

It is all about the insects: a retrospective on 20 years of forensic entomology highlights the importance of insects in legal investigations

This study highlights the importance of insect evidence by evaluating 949 insect-associated cases, including 139 entomological reports, from 2001 to 2019 at the Institute of Legal Medicine Frankfurt/Germany. With a high number of cases in the summer months and a low number in the colder season, 78.5% of the bodies were found indoors, regardless of year or month. In more than 80% of the cases, where PMI information was available (n = 704), the presumed PMI ranged from 1 to 21 days, a period during which entomological evidence can provide a day-specific estimate of PMI_min. In cases where insects have been identified to species level (n = 279), most bodies were infested by one or two species with a maximum of 10 different species. Overall, a total of 55 insect species were found. Information on biology, activity and distribution of the most abundant taxa is given and applied for 5 case histories estimating different PMI_mins of up to over 6 months. Despite proved importance and scientific development of forensic entomology, insects are still rarely considered as a tool in forensic case work. The main reasons are a lack of awareness and (too) late involvement of a forensic entomologist. Our work shows that forensic entomology is an independent discipline that requires specialist expertise.

Looking Back to Move Forward: How Review Articles Could Boost Forensic Entomology

The Locard's exchange principle (1930) holds that the perpetrator of a crime leaves traces behind that can later be sampled and used as forensic evidence [...].

Unusual Application of Insect-Related Evidence in Two European Unsolved Murders

Insect-related evidence must be considered of probative value just as bloodstains, fingerprints, fibers, or any other materials. Such evidence if properly collected and analyzed can also provide useful details in the reopening of old unsolved murders, also called "cold cases". This paper presents the case of two murders that occurred in two different European countries and remained unsolved for years. The remains of a girl found in Italy 17 years after her disappearance helped to solve a murder that occurred in Britain 8 years prior. The cases were unexpectedly linked together because of the similarities in the ritualistic placing of strands of hair and connections with the suspect. The trace evidence relating to insects and hairs played a relevant role in the conviction of the perpetrator. In Italy, the defense raised the doubt that the strands of hair found nearby the skeletal remains could be the result of insect feeding activity and not the result of a cut by sharp objects. Therefore, it was fundamental to distinguish between sharp force lesions and insect feeding activity on hair. This unusual application of insect-related evidence clearly emphasizes the importance of an appropriate professional collection and analysis of any physical evidence that could be of robust probative value.

The Relationship between Research and Casework in Forensic Entomology

Simple Summary

Forensic entomology concerns the use of insects as evidence in legal investigations. Many sorts of investigation can benefit from an interpretation of insects associated with the crime scene, but insect evidence is most frequently used in investigations of death. The interpretation of insect evidence in casework is guided by the data supplied through research. Such data are essential to improve the casework interpretation of insect evidence, thereby improving the robustness of the legal systems in which it operates. This paper explores the mutually beneficial relationship between research and casework in forensic entomology, contrasting the different challenges that each presents and giving examples of how each can support the other in delivering results of real societal benefit. It is written from the perspective of the Criminal Justice System of England and Wales, but many of the points raised are relevant to legal systems worldwide.

Abstract

Research is a vital component of all forensic sciences and is often stimulated by casework, which identifies gaps in our knowledge. In such a niche area of forensic science as entomology there should be a close and mutually beneficial relationship between research and casework: to some extent there is a continuum between the two and many forensic entomologists are involved in both to a greater or lesser degree. However, research and casework involve quite differing challenges, from the replicated, highly controlled, sometimes esoteric aspects of research to the very individual, sometimes chaotic and disruptive, but highly applied aspects of casework. Ideally casework will include the full involvement of a forensic entomologist, who will collect the insect and climate evidence at the scene and produce a robust expert witness statement based on a full analysis of this data. Unfortunately, it can also include situations where samples, if collected at all, are poorly preserved, not representative of the full cadaver fauna available and presented to the entomologist months or years after the event, without local temperature data. While research is recognised through publications and their citation indices, casework and its associated expert witness statements often receive no credit in an academic workplace, although they do have a positive societal impact and many other benefits of teaching and public engagement value. This manuscript examines the relationship between research and casework from a UK perspective, to raise awareness of the need to create an environment that values the contribution of both, for future generations to flourish in both areas.