Studying forensic entomology in the USA and Canada. Dr Andrew John Hart BSc PhD FRES Fellow 2005

Transcription

1 Insects and Death Studying forensic entomology in the USA and Canada by Dr Andrew John Hart BSc PhD FRES Fellow 2005 Forensic Scientist Forensic Science Service Ltd. A report for the Winston Churchill Memorial Trust July to September 2005

2 Acknowledgements First of all, I would like to thank the Winston Churchill Memorial Trust for giving me the opportunity of a lifetime to study forensic entomology in the USA and Canada, and the Forensic Science Service Ltd. for allowing me to take advantage of this. Secondly, I extend my thanks to my hosts in the USA and Canada whose generosity was overwhelming. They were Dr Jeff Tomberlin, Dr Jim Olson, Dr Mariana Griggs, Detective Bill Pepsis and Kellie Lander from Texas; Dr Jeff Wells and Christine Picard from West Virginia; Dr Richard Jantz, Dr Lee Jantz, Dr Murray Marks, Dr Bill Bass, Dr Steven Symes and Dr Anne Kroman from Tennessee, Dr Neal Haskell and Joel Haskell from Indiana; Dr Gail Anderson from Vancouver; and Dr M. Lee Goff from Hawaii. Last, but not least, I would like to thank Dr Martin Hall and Amoret Brandt from the Natural History Museum for their help and advice. Blowfly larvae

3 Insects and Death Dr Andrew J. Hart 3 Aim The aim of my Winston Churchill Fellowship was to learn more about forensic entomology by meeting leading experts in the USA and Canada. I aimed to achieve this by establishing contacts with American and Canadian forensic entomologists, travelling to research institutes and universities, work shadowing, completing a research project and giving presentations. I would potentially apply the knowledge and experience gained to further develop forensic entomology within the UK. General introduction Introduction I saw the Winston Churchill Fellowships advertised in the newsletter of the Forensic Science Society, and immediately thought that this could be an ideal opportunity to combine my interest in entomology (the study of insects) and forensic science. I decided upon an initial itinerary and began to make contacts with forensic entomologists in the USA and Canada. I had selected this part of the world as it had the highest concentration of forensic entomologists and there was an interesting range of opportunities available. I completed the necessary forms, obtained permission from my employer and waited nervously for a response. I knew competition would be tough, but fortunately I was short listed and passed the panel interview. I was very pleased to have reached this stage and I was now free to plan my itinerary, book flights and accommodation and hire cars. Prior planning and organisation was the key to a successful fellowship and I was pleased about the way my arrangements began to fall into place. There was a fair amount of flying involved and I was on a tight schedule, as it was all based on the availability of the forensic entomologists I was going to meet. Once the flights had been booked, contacts made and visits arranged I knew that this Fellowship was going to offer me the chance to gain a real insight into forensic entomology. My background I am a forensic scientist working at the Forensic Science Service Ltd., specializing in the examination of biological evidence, which includes the identification of body fluid staining and the interpretation of DNA profiling results. I produce statements for court and I am trained as an expert witness. Prior to this, I trained and worked as an applied

4 Insects and Death Dr Andrew J. Hart 4 entomologist for over eight years. I studied for a PhD at the University of Birmingham on the effects of temperature on the growth and development of hoverflies in the UK. I continued my research at the University during a post-doctoral research fellowship on the biological control of insect pests, before becoming a Research Leader in applied entomology at Horticulture Research International. I had twelve scientific papers published on my scientific research during my academic career. I am working towards combining my training as an entomologist with my role as a forensic scientist in the form of forensic entomology. What is forensic entomology? Forensic entomology is the interpretation of insect evidence to help in criminal investigations. It involves the study of the biology, behaviour and distribution of insects at a crime scene, which can give information on when, where and how a crime was committed. The key aspect of forensic entomology is the estimation of minimum time since death or post-mortem interval (PMI). However, it can also provide clues with regard to the possible movement of a corpse, in cases of abuse or neglect, food infestations and toxicological studies. Insects can also form potential sources of human DNA after feeding on a corpse, which can provide additional information in a murder investigation. Blowflies (bluebottles and greenbottles) are the key group of forensically important insects for a number of reasons. They are the most commonly found insects on dead bodies and are usually the first insects to arrive at a corpse, whereupon they begin to feed and lay eggs. Blowfly larvae (maggots) are the critical stage used in estimating the minimum time of death. It is important to have an understanding of the life cycle of blowflies when studying the role of these Blowfly larvae

5 Insects and Death Dr Andrew J. Hart 5 insects in the decomposition of a dead body. Adult flies are attracted to the openings in the head (nose, mouth, eyes), anus, genitals and any wounds that may be present on the body, where they lay their eggs in masses around these sites. The eggs hatch out into first stage (instar) larvae and pass through two more stages, before leaving the body as post-feeding or wandering larvae. The larvae move away from the body, often forming long trails, and subsequently bury into the soil. They change into puparia in the ground and adult flies form within the puparial cases. The adult flies break out of their cases, crawl up through the soil and are then free to begin feeding, mating and laying eggs again. With an in depth knowledge of insect, particularly blowfly, biology, behaviour and distribution it is then possible to estimate the minimum time of death of a person. It is useful to describe decomposition of the body at the crime scene and to note any insect activity. After this, it is important to collect insect specimens following the correct protocol so that the insects can then be analysed at the laboratory. The insects need to be identified and their life stage Collections of blowflies noted. Any blowfly larvae collected are aged by using their size and estimates of temperatures that they may have been exposed to before reaching that stage. The age of maggot gives an estimate of the period of insect activity on the body or the minimum time since death. Death may have occurred before the insect activity commenced as the insects may have been prevented access to the body until later, for instance if the body was in a sealed container. It is important to gain hands on experience of forensic entomology including insect sampling techniques at a crime scene, insect identification, time of death calculations, casework and research. The Winston Churchill Fellowship allowed me to have this unparalleled opportunity.

6 Insects and Death Dr Andrew J. Hart 6 Itinerary - Summer 2005 The Fellowship Florida - North American Forensic Entomology Association (20 th to 22 nd July) Texas - Dr Jeff Tomberlin, Texas A&M University (25 th to 29 th July) West Virginia - Dr Jeff Wells, West Virginia University (1 st to 5 th August) Tennessee - Anthropological Research Facility (8 th to 26 th August) Indiana - Dr Neal Haskell, St Joseph s College (29 th August to 2 nd September) Vancouver - Dr Gail Anderson, Simon Fraser University (5 th to 9 th September) Hawaii - Dr M. Lee Goff, Chaminade University (12 th to 16 th September) Map showing route across the USA and Canada

7 Insects and Death Dr Andrew J. Hart 7 North American Forensic Entomology Association Conference, Orlando, Florida I attended the North American Forensic Entomology Association (NAFEA) conference at Disney World, Orlando, Florida. It gave me the opportunity to make initial contact with a large number of experts as well as meeting some of the forensic entomologists that I was going to be seeing later in the trip. There were a series of presentations on forensic entomology together with topical discussions. I became a member of the NAFEA and there is also the potential for me to become an accredited forensic entomologist with appropriate experience. Dr Jeff Tomberlin, Texas A & M University, Stephenville and College Station, Texas My next stop was Dallas, Texas, from where I travelled down to Texas A & M University at Stephenville and College Station to meet Dr Jeff Tomberlin. He is an assistant Professor of entomology, President of the NAFEA and one of America s up and coming forensic entomologists. He carries out research on forensic and animal health entomology while working on cases alongside this. I was also introduced to two other forensic entomologists during my visit, Dr Jim Olson and Marianna Griggs. Dr Jeff Tomberlin Catching flies on a dead goat Dr Tomberlin kindly provided me with a dead goat to study during my stay in Texas. I made a photographic record of its decomposition and collected insects from various sites of the body and at different times of the day. I preserved and pinned the insects that I had collected and identified a number of them by using taxonomic keys. We discussed his casework and he allowed me to study and make copies of his substantial literature collection. Dr Olson showed me his work on pig decomposition, discussed his casework and he

8 Insects and Death Dr Andrew J. Hart 8 guided me through his mosquito research involving transmission of West Nile Virus. I gave a presentation to students at the university on my entomology research and role as a forensic scientist. The generosity of Dr Tomberlin, his wife, colleagues and family was in true Texan style, with the provision of huge steaks, grill outs and strawberry pie. As well as learning a great deal about forensic entomology, I also experienced some of the famed southern hospitality during my stay. On my last day in Texas, I travelled back to Dallas to visit the Dallas Police Department and Dallas County Forensic Institute, which my Dallas friend, Kellie Lander, had kindly helped to arrange for me. Detective William Pepsis, lead trainer in the Crime Scene Investigation (CSI) Unit took time to discuss the CSI training programme and the role of the investigator at crime scenes in Dallas, and how forensic entomology would be part of this. I was given a tour of the unit, including the DNA labs, fingerprint section, gun department and blood room. He introduced me to the Chief Medical Examiner, David Gabutz, who discussed his role as a medical examiner while guiding me around the morgue and autopsy suites. They have to contend with a huge number of unnatural deaths on an annual basis partly due to the fact that Dallas has one of America s highest murder rates. I was impressed with the way they dealt with this. Dr Jeff Wells, West Virginia University, Morgantown, West Virginia I flew from Dallas to Pittsburgh, where I was greeted by Dr Jeff Wells, an Associate Professor of forensic science based at West Virginia University in Morgantown, West Virginia. Dr Wells is a leading expert in use of DNA technology in relation to forensic entomology, using DNA West Virginia University techniques to identify forensically important flies. The

9 Insects and Death Dr Andrew J. Hart 9 techniques include the gathering of mitochondrial DNA sequence data followed by phylogenetic analysis (construction of family trees of flies). There is a real need for such methods of identification as it can be difficult to identify immature flies using traditional techniques, as the samples may be degraded or at early life stage such as the egg or first instar larvae. It is also possible to identify whether or not there is human DNA contained in the larval gut after they have been feeding on a body. This makes it possible to tell whether or not a particular larva, which may have moved away from the body, has been feeding on the corpse, and therefore it can be used in the estimation of the minimum time of death. Also if a body has been moved, it is sometimes possible to obtain an identity of person from human DNA extracted from any larvae that remain behind at the crime scene having fallen from the body. Collected road kill Dr Wells and his colleagues instructed me in the identification of flies and their larvae using both DNA and traditional techniques. This gave me hands on experience of these methods and a valuable insight into the advantages of the application of modern techniques. I spent part of my time in the countryside of West Virginia with a postgraduate student, Christine Picard, in order to collect road kill, as it acts as an attractant to carrion feeding flies and other associated insects. We collected the insects from the rotting corpses to identify and preserve them as well as to add to Christine s laboratory insect colonies. I am grateful to Dr Wells, his wife, colleagues, students and friends for making me very welcome during my stay in West Virginia, and for giving me the opportunity to learn some important techniques in the field of forensic entomology.

10 Insects and Death Dr Andrew J. Hart 10 Anthropological Research Facility, University of Tennessee, Knoxville, Tennessee My next stop on the Fellowship was for a three week stay at Knoxville, Tennessee to visit the Anthropological Research Facility (ARF) run by the Department of Anthropology at the University of Tennessee. The ARF is also infamously known as the Body Farm, as used by the crime author Patricia Cornwell as the title of one of her novels. Upon my arrival, I was greeted by Dr Richard Jantz, a Professor of Anthropology and the director of the ARF, Dr Lee Jantz, the coordinator of the body donation programme and Anne Entrance to Anthropological Research Facility Kroman, a postgraduate researcher. I was also introduced to Dr Murray Marks, an Associate Professor of Anthropology and Dr Steven Symes, an Assistant Professor in Anthropology and specialist in dismemberment cases. Once I had overcome my initial trepidation, the next three weeks working at the ARF proved to be an extremely interesting and informative experience.

11 Insects and Death Dr Andrew J. Hart 11 Professor Bill Bass, a pioneer of forensic anthropology, founded the ARF in 1980 in order to deepen the understanding of physical anthropology, particularly in relation to time of death estimations in forensic cases. I had the pleasure of meeting Professor Bass during my research at the ARF. It is a three-acre site situated on a wooded hillside close to a hospital just outside of Knoxville. Scientific research is carried out at the facility into the decomposition of humans and the establishment of time since death. The skeletons are cleaned, sorted and added to the Department of Anthropology s collection for further study and research. The advantage of this collection is that Dr Bill Bass and Dr Andrew Hart the prior history of the individual is known, so the bone structure can be related to this for research purposes and for when comparisons are made to unknown bones collected from a crime scene. The ARF is also used for body recovery training courses for the FBI. Approximately eighty to one hundred bodies are donated each year, primarily by their owners and families, but also from medical schools, and occasionally unclaimed homeless people or murder victims, if the bodies have not been claimed from the morgue after six months have passed. The coordinator stressed that there was no way to predict when they would receive a new donor; sometimes they may not have any for a few weeks while at other times they may have a number donated within a few days. I was fortunate enough to be able to study two donor bodies during my stay. The Facility collect donors within a 250 mile radius of the site, otherwise the donor s family are required to organize delivery to the hospital morgue. From the morgue, they are transported to the Facility, and are House and car used in crime scene scenarios generally placed on the ground still

12 Insects and Death Dr Andrew J. Hart 12 within their body bag. As most scientists at the Facility are interested in studying the bones, the cadavers can be left in situ for up to a year until the flesh rots away. However, for research purposes they can be placed exposed in the open, clothed or naked and also in various crime scene scenarios, for example in a car boot, indoors or buried. Impression of a body left in concrete I was only the second entomologist from UK to have visited the ARF, after Amoret Brandt of the Natural History Museum, London, and only the fifth entomologist in the world. Therefore, it was a rare opportunity for me to be able carry out research there. I designed a research project, in collaboration with the Natural History Museum, which involved the study of insect activity in relation to the decomposition of dead bodies. I basically monitored insect attraction, selection of oviposition (egg-laying) sites, larval development, formation of maggot masses, larval migration and selection of pupation sites. I recorded ambient, rectal, oral and dorsal temperatures of the bodies using data loggers and probes (see Fig.1). In addition, I monitored temperatures of the maggot masses that formed using a non-invasive infra-red thermometer and sometimes temperatures reached over forty five degrees centigrade. I created a photographic record of decomposition of the two donor bodies, taking pictures twice a day, every day, for three weeks from the same angles each time. At the same times of day, I collected eggs, larvae, pupae and adult insects that were present on and around the body, resulting in the formation of a substantial insect collection. I made a written record of the insect activity and state of decomposition, which included Net and kill jar for adult insects

13 Insects and Death Dr Andrew J. Hart 13 the monitoring and measuring of the post-feeding migration of larvae away from the body. Back in the laboratory, I reared some of the specimens that I had collected in order to ease the identification of the insects. Temperature ( C) ) Am bient Back Oral Rectum Date Fig. 1 A m bient, low er back, oral and rectal tem peratures of fem ale at the Anthropological Research Facilty, August 2005 Decomposition itself consists of a number of processes including the enzymatic liquefaction of cells, bacterial decomposition of tissue, the drying of the skin and remaining soft tissue, followed by skeletonisation. The rate at which this occurs depends on environmental conditions, particularly temperature and humidity. The two bodies I worked on demonstrated almost the whole process of decay, as the temperature and humidity during August in Tennessee provided almost ideal conditions for bacterial and insect activity. Therefore, I was able to observe almost the whole sequence of events that occur in the decomposition of a dead body. The female donor rapidly progressed from fresh to almost skeletonised in only nineteen days. There was

14 Insects and Death Dr Andrew J. Hart 14 a large amount of insect activity, with thousands of larvae forming huge maggot masses on the body. Insect activity has a major role to play in the decomposition of a human body; in fact the human body can lose up to sixty per cent of its mass in a week to maggot feeding activity. Decomposition and related insect activity forms a continuum but has been divided into a number of stages for ease of explanation. The fresh stage includes the time when blowflies Inside the Anthropological Research Facility are attracted to the body to begin feeding and egg laying, especially around the head, anus, genitals and open wounds. During the bloated stage a variety of changes occur including putrefaction, the release of gases from the activity of anaerobic bacteria, maggot feeding which helps to cause increases in the temperature of the body, the attraction of many blowflies and the leakage of fluids from the body and ammonia from the metabolic activity of larvae which makes the local soil alkaline in nature. The skin breaks and the gases escape leading to deflation during the decay stage. Maggot masses and beetles are also present in this stage, and larvae start leaving the body to pupate in the soil. Most of the flesh has been removed before entering the post decay stage, leaving skin, cartilage and bones, beetles are more common. Finally, in the skeletal stage, all that remains of the body are bones and hair, with few or no carrion insects present. Working conditions were fairly challenging as temperatures were regularly over thirty five degrees centigrade in August with high humidity and hundreds of mosquitoes, but it was a real opportunity to work in an area where few other people have. My study visit made me fully appreciate the processes involved in decomposition and the vital role insects played in this. It made me realise how important insects actually were and it was truly fascinating to watch the speed at which they developed on the body. Seeing thousands of maggots all migrating in one long trail from the body, having completed their feeding, was an impressive sight. It was extremely useful to have had first-hand experience of observing how insects have such an important role in decomposition. The data that I

15 Insects and Death Dr Andrew J. Hart 15 have collected will prove invaluable once it has been analysed, and it will hopefully be published as a scientific paper in collaboration with the Natural History Museum. There is a real need for fundamental research such as this in forensic entomology. Dr Neal Haskell, St Joseph s College, Rensselaer, Indiana Dr Neal Haskell is a Professor of forensic science and biology at St Joseph s College and is America s only independent forensic entomologist, working on an average of forty to fifty cases on an annual basis. He has an impressive knowledge of the subject, having coauthored a manual of forensic entomology, and is one of the most experienced caseworkers. He also runs an extensive research program using pigs as models of human decomposition. Dr Haskell guided me through a number of his live cases, and he allowed me to carry out preliminary identification of the flies. We discussed in detail a number of his high profile cases involving forensic entomology and his subsequent court appearances as an expert witness. It made for fascinating and informative discussions. During the week, I observed the decomposition and insect activity on three pigs that Dr Haskell had generously provided Dead pigs in Indiana for me, from which I collected and identified carrion feeding insects. I also assisted in a debate during one of his forensic science classes and helped in the teaching of an outdoor crime scene class. Dr Haskell, his family and students showed excellent hospitality towards me and made me feel very much at home in Indiana. I learnt a great deal about forensic entomology and its application to criminal investigations. Dr Gail Anderson, Simon Fraser University, Vancouver, British Columbia Dr Gail Anderson is Canada s leading forensic entomologist as well as being an Associate Professor of forensic science and Associate Director of the undergraduate forensic program at Simon Fraser University. Dr Anderson runs an extensive research

16 Insects and Death Dr Andrew J. Hart 16 Simon Fraser University program including monitoring the decomposition of submerged pigs in the ocean and the effect of fire on insect evidence on bodies. We discussed this research in depth, and I viewed a number of videos showing the research on underwater pigs and fire damaged properties containing dead pigs. I learnt more about the calculations used to estimate the minimum time of death in live casework, which is an essential component of any case involving forensic entomology. Dr Anderson introduced me to a wide range of her colleagues, from anthropologists to criminologists, which gave me an insight to other areas in forensic science. I had the opportunity to visit the British Columbia Institute of Technology, which runs a forensic training program for police personnel. During the week, I gave a presentation on forensic science in the UK to the forensic students at Simon Fraser University, as it was the start of their Autumn Term. Dr Gail Anderson generously spent time away from her academic role to give me an insight into how forensic entomology is practiced in Canada, and also how it fitted into the wider area of forensics in a University environment. Dr M. Lee Goff, Chaminade University, Oahu, Hawaii Last but not least, I went on to meet Dr. M. Lee Goff who is based at Chaminade University in Honolulu, Oahu, Hawaii. Dr Goff is the chair of the forensic program at the University, a Professor of forensic entomology and one of the worlds leading practitioners, with over twenty years experience in the field. He has been involved in hundreds of cases across the USA, backed up by an extensive research based Dr M. Lee Goff background. He is the author of the book A Fly for the Prosecution as well as being a consultant for the popular fictional forensic television programme CSI. While in Hawaii I observed pig decomposition and insect

17 Insects and Death Dr Andrew J. Hart 17 activity and discussed his casework and research. I was also able to add to my now substantial literature collection. Dr Goff again demonstrated a willingness to help in my objective to learn more about forensic entomology, and was generous to a fault in extending me some Hawaiian hospitality on the last stop of my Fellowship. Conclusions Outcomes and follow up On my return to the UK, I have been busy capitalising on the success of my Fellowship both in terms of publicity and the benefits to my career in forensic science, although I still have a great deal of work to do. I am aiming to analyse the insect samples that I have brought back from the ARF and to identify the specimens. I shall also be producing a display case with the best specimens, to be used as an educational tool and for reference purposes. Once I have analysed the samples and related this data to the recorded temperatures and stage of decomposition, I shall submit the results for publication in the scientific press. I shall maintain links with the forensic entomologists that I met during the Fellowship, with possible collaborative research projects being undertaken in the future. I have also been invited to return to the ARF to carry on with my research. Insect samples One of the objectives of a Fellowship was to promote and publicise the Winston Churchill Memorial Trust and its Fellowships. I believe that I have made substantial progress with this, and it is still ongoing. I organised press releases in liaison with Lucy Stokes, from the Communications Group at FSS Ltd. As a result of this, there was extensive media interest in my trip, which led to articles in the Metro News, Police Professional (which is distributed to 20,000 police officers), Clued Up (an internal publication at FSS Ltd.), Lab News, Rugby Advertiser, and Lawrence Sheriff School newsletter. There were also seven pages on ITV Teletext about my Fellowship. I have

18 Insects and Death Dr Andrew J. Hart 18 had interest from the Sunday Express, Birmingham News Team, BBC 1 drama producers, Channel 4 documentary makers and the Wellcome Trust in conjunction with Channel 5 (discussing the CSI effect ). As well as the media interest, I have been invited to give talks to a number of audiences including pathologists at the national meeting of the Association of Clinical Pathologists in Prague and to students and staff at Kings College London, London Metropolitan University, Wolverhampton University and Southbank University amongst others. The Forensic Science Society and researchers at Exeter University and the University of Central Lancashire expressed an interest in my studies on forensic entomology. I organised a display stand demonstrating the potential of forensic entomology at an open day at FSS Ltd., which proved to be hugely popular amongst staff and their family and friends. Staff from FSS Ltd., police officers and forensic science students have approached me on an individual basis either in person or by to talk about their interest in forensic entomology and how impressed they were by my Fellowship. Conclusion I have learnt a huge amount about forensic entomology, which really would not have been possible by just reading books and papers. To have actually seen the insects in action taught me so much more than that. I experienced many different ways of working by visiting so many different forensic entomology practitioners, which was an excellent opportunity for me. I met the aim of my Fellowship, which was to study and learn more about forensic entomology by meeting leading experts in the USA and Canada. I achieved this by developing contacts with American and Canadian forensic entomologists at various universities and research institutes, completing a research project and by giving presentations. Forensic entomology is an under-exploited area of forensic science and I am hoping to share my research and promote its wider use. None of this would have been possible without the opportunity provided to me by the Winston Churchill Memorial Trust and the support from my employer. It certainly was a chance of a lifetime and has benefited me in more ways than I could ever have imagined and I thoroughly recommend anyone to apply for one.