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- Herausgeber: John Wiley & Sons
- Kategorie: Wissenschaft und neue Technologien
- Sprache: Englisch
A completely revised and updated edition that teaches the essentials of forensic biology, with increased coverage of molecular biological techniques and new information on wildlife forensics, wound analysis and the potential of microbiomes as forensic indicators
This fully revised and updated introduction to forensic biology carefully guides the reader through the science of biology in legal investigations. Full-colour throughout, including many new images, it offers an accessible overview to the essentials of the subject, providing balanced coverage of the range of organisms used as evidence in forensic investigations, such as invertebrates, vertebrates, plants and microbes. The book provides an accessible overview of the decay process and discusses the role of forensic indicators like human fluids and tissues, including bloodstain pattern analysis, hair, teeth, bones and wounds. It also examines the study of forensic biology in cases of suspicious death.
This third edition of Essential Forensic Biology expands its coverage of molecular techniques throughout, offering additional material on bioterrorism and wildlife forensics. The new chapter titled ‘Wildlife Forensics’ looks at welfare legislation, CITES and the use of forensic techniques to investigate criminal activity such as wildlife trafficking and dog fighting. The use of DNA and RNA for the identification of individuals and their personal characteristics is now covered as well, along with a discussion of the ethical issues associated with the maintenance of DNA databases.
- Fully revised and updated third edition of the successful student-friendly introduction to the essentials of Forensic Biology
- Covers a wide variety of legal investigations such as homicide, suspicious death, neglect, real and fraudulent claims for the sale of goods unfit for purpose, the illegal trade in protected species of plants and animals and bioterrorism
- Discusses the use of a wide variety of biological material for forensic evidence
- Supported by a website that includes numerous photographs, interactive MCQs, self-assessment quizzes and a series of questions and topics for further study to enhance student understanding
- Includes a range of important, key case studies in which the difficulties of evaluating biological evidence are highlighted
Essential Forensic Biology, Third Edition is an excellent guide for undergraduates studying forensic science and forensic biology.
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Table of Contents
Cover
Introduction
Acknowledgements
About the Companion Website
Part I: Decay and the Discovery and Recovery of Human Remains
1 The Decay of Human Bodies
1.1 Introduction
1.2 The Stages of Decomposition
1.3 Factors Affecting the Speed of Decay
1.4 Future Directions
2 The Discovery, Recovery, and Study of Human Bodies
2.1 Discovery of Human Remains
2.2 Recovery of Dead Bodies
2.3 The Post Mortem
2.4 Determining the Age of Skeletonised Remains
2.5 Determining the Provenance of Skeletonised Remains
2.6 Future Directions
Part II: DNA Analysis
3 Molecular Biology
3.1 Introduction
3.2 DNA Sampling
3.3 DNA Analysis
3.4 Molecular Markers
3.5 DNA Databases
3.6 Confounding Factors in DNA Analysis
3.7 Evidence from Molecular Markers
3.8 Future Directions
Part III: Body Tissues and Fluids and Wound Analysis
4 Blood
4.1 Blood Cells and Blood Typing
4.2 Distinguishing Human and Animal Blood
4.3 Bloodstain Pattern Analysis
4.4 Fake Blood
4.5 Post‐Mortem Toxicological Analysis of Blood
4.6 Future Directions
5 Saliva, Semen, Vitreous Humour, Urine, and Faeces
5.1 Saliva
5.2 Semen
5.3 Vitreous Humour
5.4 Faeces
5.5 Urine
5.6 Summary of Forensic Information Obtained from Body Fluids and Waste Products
5.7 Future Directions
6 Human Tissues
6.1 The Outer Body Surface
6.2 The Skeleton
6.3 Teeth
6.4 Summary of Forensic Evidence that can be obtained from Human Tissues
6.5 Future Developments
7 Wounds
7.1 Introduction
7.2 Blunt Force Injuries
7.3 Sharp Force Traumas
7.4 Bone Damage
7.5 Bite Marks
7.6 Asphyxia
7.7 Pathology Associated with Drug Use
7.8 Burns and Scalds
7.9 Gunshot Wounds
7.10 Wounds Caused by Explosions
7.11 Complex Suicides
7.12 Ageing of Wounds
7.13 Post‐Mortem Injuries
7.14 Future Developments
Part IV: Invertebrates
8 Invertebrates 1
8.1 An Introduction to Invertebrate Biology
8.2 Invertebrates as Forensic Indicators in Cases of Murder or Suspicious Death
8.3 Parasitoid Wasps
8.4 Insects on Buried Bodies
8.5 Future Directions
9 Invertebrates 2
9.1 Introduction
9.2 Collecting Invertebrates for Forensic Analysis
9.3 Killing and Preserving Techniques for Invertebrates
9.4 Invertebrate Identification Techniques
9.5 Calculating the PMI/Earliest Oviposition Date
9.6 Complicating Factors Affecting Earliest Oviposition Date Calculations
9.7 Other Evidence from Invertebrates
9.8 Future Directions
Part V: Vertebrates and Wildlife Crime
10 Vertebrates
10.1 Introduction
10.2 Identification of Vertebrates
10.3 Vertebrate Scavenging of Human Corpses
10.4 Vertebrates Causing Death and Injury
10.5 Neglect and Abuse of Vertebrates
10.6 Vertebrates and Drugs
10.7 Future Directions
11 Wildlife Forensics
11.1 Introduction
11.2 When it is Legal to Kill or Exploit Wildlife
11.3 The Extent of the Trade in Wildlife
11.4 CITES
11.5 Factors that Contribute to the Illegal Trade in Wildlife
11.6 Poaching
11.7 Bushmeat
11.8 Ivory
11.9 Antlers
11.10 Horns
11.11 Bear Bile
11.12 Musk Oil
11.13 The Illegal Trade in Invertebrates
11.14 Future Directions
Part VI: Plants, Protists, Fungi, and Microbes
12 Protists, Fungi, and Plants
12.1 Introduction
12.2 Protists
12.3 Fungi
12.4 Plants
12.5 Plant Secondary Metabolites as Sources of Drugs and Poisons
12.6 Illegal Trade in Protected Plant Species
12.7 Summary of the Forensic Potential of Protists, Fungi, and Higher Plants
12.8 Future Directions
13 Microbes and Viruses
13.1 Introduction
13.2 Microbiomes
13.3 Microbes and Viruses as Indicators of Geographical Origin
13.4 Microbes and the Cause of Death
13.5 Identification of Microbes Responsible for Food Poisoning
13.6 Linking a Victim and a Suspect through the Transfer of Microbial and Viral Infections
13.7 Pathogens and Human Behaviour
13.8 Interactions between Microbes, Viruses and Drugs
13.9 The Use of Microorganisms in Bioterrorism
13.10 Future Directions
References
Index
End User License Agreement
List of Tables
f04
Table I.1 Questions arising when a body is found in suspicious circumstances.
Table I.2 Characteristics of an ideal forensic test.
Chapter 1
Table 1.1 Factors affecting the rate at which a body cools after death.
Table 1.2 Summary of the stages of decomposition and their characteristic featur...
Table 1.3 The sequence in which insects arrive and colonise a corpse during the ...
Table 1.4 Summary of factors promoting or delaying the rate at which a body deca...
Chapter 2
Table 2.1 Summary of the advantages and disadvantages of the main methods of det...
Chapter 3
Table 3.1 Potential sources of human DNA for forensic analysis.
Table 3.2 Summary of reactions involved in the polymerase chain reaction (PCR).
Table 3.3 Advantages and disadvantages of the most commonly used methods of fore...
Table 3.4 STR loci used in the SGM+, DNA‐17, CODIS, and expanded CODIS loci.
Table 3.5 Table of alleles illustrating the hypothetical DNA profile of a semen ...
Table 3.6 Case study of paternity determination from aborted chorionic villi: ST...
Table 3.7 Information stored on individuals on the NDNAD.
Table 3.8 The application of DNA sequencing to forensic investigations.
Chapter 4
Table 4.1 Summary of ABO blood group interactions.
Chapter 5
Table 5.1 Summary of forensic information obtained from body fluids and waste pr...
Chapter 6
Table 6.1 Typical emergence dates of different types of teeth in normal healthy ...
Table 6.2 Summary of forensic evidence obtainable from human tissues.
Chapter 7
Table 7.1 Summary of wound types and their causes.
Table 7.2 Categories of asphyxia.
Table 7.3 Factors that determine the consequences of a bullet hitting its target...
Table 7.4 Distinguishing features of wounds associated with suicide and homicide...
Table 7.5 Summary of some of the instances in which an accurate estimation of wh...
Chapter 8
Table 8.1 Groups of invertebrates attracted to decaying remains.
Table 8.2 Taxonomy of the order Diptera.
Table 8.3 Coleoptera families of forensic importance.
Chapter 9
Table 9.1 Summary of killing and preservation methods for soft‐ and hard‐bodied ...
Table 9.2 Comparison of traditional morphology‐based taxonomy and molecular (DNA...
Table 9.3 Summary of morphological age indicators in cyclorrhaphan flies at diff...
Table 9.4 An example of the headings and completed spreadsheet to calculate the ...
Table 9.5 Summary of factors that can complicate the minimum time since death ca...
Table 9.6 Summary of insect evidence that suggests that a body was moved after d...
Chapter 10
Table 10.1 Summary of vertebrate animals and their forensic relevance.
Table 10.2 The three basic types of bird feather.
Chapter 11
Table 11.1 Factors driving poaching and the illegal trade in wildlife.
Table 11.2 Why rapid field tests are useful in wildlife forensics.
Table 11.3 The market for Lepidoptera.
Chapter 12
Table 12.1 The advantages and limitations of pollen as a forensic indicator.
Table 12.2 Summary of forensic information gained from protists, fungi, and high...
Chapter 13
Table 13.1 The benefits and limitations of microbiomes as forensic indicators.
Table 13.2 Some human pathogens investigated as biowarfare agents in the past or...
Table 13.3 Clues that would provide an early indication of the malicious spreadi...
Table 13.4 Some domestic animal pathogens investigated as biowarfare agents in t...
List of Illustrations
Chapter 1
Figure 1.1 Clauss Henßge's nomogram for the determination of time since death f...
Figure 1.2 Characteristic pattern of hypostasis and pressure pallor resulting f...
Figure 1.3 Late bloat stage of decomposition. The body is about seven days old ...
Figure 1.4 The formation of adipocere has preserved the body of this child, des...
Figure 1.5 (a) The body of this man was discovered 5.5 months after he committe...
Chapter 3
Figure 3.1 Diagrammatic representation of the PCR thermal cycling process. Each...
Figure 3.2 Diagrammatic representation of the amplification step of the PCR pro...
Figure 3.3 Diagrammatic representation of the multiplex PCR process. (a) The ar...
Figure 3.4 Electropherograms of autosomal STR profiles. (a) An SGM Plus profile...
Figure 3.5 Diagrammatic representation of the TaqMan assay.
Figure 3.6 Diagrammatic representation of (a) heteroplasmy and (b) homoplasmy a...
Figure 3.7 Diagrammatic representation of a single nucleotide polymorphism.
Chapter 4
Figure 4.1 Blue luminescence following treatment with luminol indicates the (pr...
Figure 4.2 Factors affecting the spatter pattern of passively falling droplets ...
Figure 4.3 The flow of blood vertically down the chest and abdomen from a neck ...
Figure 4.4 Transfer bloodstain from a bloody finger on a tap. Transfer stains l...
Figure 4.5 This man was shot in the head. Because his body is on an incline, th...
Figure 4.6 Blood spatter from gunshot wounds: (a) backspatter stains on the rig...
Figure 4.7 This stain was caused when the victim slit their wrist. It exhibits ...
Figure 4.8 Smeared bloodstain pattern formed by dragging a bloody body across t...
Figure 4.9 (a)–(c) The influence of angle of impact on the shape of bloodstain....
Figure 4.10 Diagrammatic representation of how the length of an elliptical bloo...
Figure 4.11 (a) and (b) Diagrammatic representation of how the point of converg...
Figure 4.12 Bloodstain pattern analysis using ‘stringing’.
Figure 4.13 Determination of the area of haemorrhage (origin) by the graphics m...
Chapter 6
Figure 6.1 Tattoos that have a limited appeal help in the identification proces...
Figure 6.2 Different types of fingerprints: (a) plastic fingerprint left in pla...
Figure 6.3 Fingerprint characteristics showing the distinction between arches, ...
Figure 6.4 Vacuum Metal Deposition is extremely good at revealing latent prints...
Figure 6.5 Scanning electron micrograph of human hair: (a) scalp hair; and (b) ...
Figure 6.6 Retinal surface of left and right eyes, illustrating the complex net...
Figure 6.7 It is easy to mistake manmade and natural objects for bones or bone ...
Figure 6.8 Pelvis of adult male (a) and female (b).
Figure 6.9 The skulls of adult humans can usually be ascribed to one of three r...
Chapter 7
Figure 7.1 Diagrammatic representation of different types of wound to the skin....
Figure 7.2 Bruising. (a) Bruising and scratch marks resulting from manual stran...
Figure 7.3 Elderly people bruise easily and repetitive and/or forceful movement...
Figure 7.4 Crush abrasions caused by beating with a leather riding‐crop. Note h...
Figure 7.5 Suicidal hanging. This man hung himself using a wire rope wound twic...
Figure 7.6 Incised wounds that are longer than they are deep and inflicted with...
Figure 7.7 This individual was found naked in a field. He was still alive but d...
Figure 7.8 This individual slashed and stabbed at his leg in a suicide attempt....
Figure 7.9 Diagrammatic representation of the larynx showing the commonest frac...
Figure 7.10 The formation of a ‘foam cone’ – the accumulation of froth at the m...
Figure 7.11 This man was shot in the forehead from close range with a small cal...
Figure 7.12 Suicide bomber killed by a shot from an assault rifle before he cou...
Figure 7.13 Remains of a suicide bomber after detonating his explosives. The bo...
Chapter 8
Figure 8.1 Blowflies ovipositing within and around the nasal cavity of a sheep....
Figure 8.2 Blowfly eggs laid upon vegetation underneath a body. Although the eg...
Figure 8.3 Anterior of the third instar larva of the blowfly
Calliphora vomitor
...
Figure 8.4 (a) Adult fleshfly
Sarcophaga carnaria
(Sarcophagidae). Note the lar...
Figure 8.5 Posterior spiracles of
Musca domestica
larvae: (a) third instar larv...
Figure 8.6 (a)
Calliphora vicina
third instar blowfly larva. The full crop indi...
Figure 8.7 (a) Adult phorid flies (note the humped profile) and an empty pupari...
Figure 8.8 Larva (top image) and pupa (bottom image) of the hoverfly
Eristalis
...
Figure 8.9 Final instar stratiomyid larva. Stratiomyid larvae are common soil i...
Figure 8.10 (a) Trichocerid larva. Note the well‐developed head capsule. (b) Sc...
Figure 8.11 (a) Adult
Dermestes maculatus
feeding and laying eggs on a fresh de...
Figure 8.12 Damage caused to a museum specimen of a dry stuffed rat by the larv...
Figure 8.13 Hypopus stage of the mite
Myianoetus muscarum
. The mites lack feedi...
Figure 8.14 This sheep was eviscerated after death, probably by foxes or badger...
Figure 8.15 Predatory beetle larvae. (a) Larva of a staphylinid beetle. (b) Lar...
Figure 8.16 Silphid burying beetles: (a)
Nicrophorus vespilloides
; (b)
Thanatop
...
Figure 8.17 Post‐mortem wounds caused by
Nicrophilus vespilloides
and
Nicrophil
...
Figure 8.18 Scanning electron micrograph image of adult parasitoid wasp
Nasonia
...
Figure 8.19 Common human lice: (a) Human head louse
Pediculus humanus humanus
. ...
Chapter 9
Figure 9.1 Blowflies can be reared inside plastic plant cloches that are stored...
Figure 9.2 These maggots were originally the same size: one was killed in near‐...
Figure 9.3 (a) Pupariae of the blowfly
Calliphora vicina
. Note how the cuticle ...
Figure 9.4 Characteristic features of recently emerged blowflies. (a) The body ...
Figure 9.5 Isomegalen‐diagram for the blowfly
Lucilia sericata
. Time (
x
‐axis) i...
Figure 9.6 Calculation of the base temperature.
Figure 9.7 A localised rise in temperature is not restricted to the mass feedin...
Chapter 10
Figure 10.1 Dead badger (
Meles meles
) found by the side of the road. In the UK,...
Figure 10.2 Confiscated orang‐utan (
Pongo pygmaeus
) skull. Orang‐utans are CITE...
Figure 10.3 Illegally killed and crudely stuffed sparrowhawk (
Accipiter nisus
)....
Figure 10.4 Guard hair microstructure. (a) Cow hair, whole mount, (b) dog hair,...
Figure 10.5 Red blood cell microstructure. (a) Mammalian red blood cells (human...
Figure 10.6 Barbules of (a) chicken (
Gallus gallus domesticus
), (b) moorhen (
Ga
...
Figure 10.7 (a) Carrion crow (
Corvus corone
); (b) eyes pecked out of a recently...
Chapter 11
Figure 11.1 Tunnel trap used to capture stoats and weasels on a grouse moorland...
Figure 11.2 (a) Carved elephant ivory. The shape and a size of the tusk identif...
Figure 11.3 Deer farm in the Ukraine. These deer are kept primarily for their a...
Figure 11.4 African white rhinoceros
Ceratotherium simum
: (a) the horn is rough...
Figure 11.5 Gift package of bear bile for use as Chinese Traditional Medicine.
Chapter 12
Figure 12.1 (a) and (b) Light microscope photograph of freshwater diatoms. Note...
Figure 12.2 Algal growth on a dry sheep skull. Growth is most pronounced on the...
Figure 12.3 Fungal mycelia growing on a corpse. The mycelia interfere with taki...
Figure 12.4 Fly agaric mushroom,
Amanita muscaria
. This distinctive mushroom is...
Figure 12.5 Although wood from different trees often looks similar, its microsc...
Figure 12.6 Pollen morphology: (a)
Poa pratensis
(smooth meadow grass) pollen (...
Figure 12.7 Rhododendron pollen is the source of ‘mad honey’– note the distinct...
Figure 12.8 Goosegrass (
Galium aparine
). Note the hooks on the fruit.
Guide
Cover
Table of Contents
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Essential Forensic Biology
Third Edition
Alan Gunn
School of Natural Sciences & PsychologyLiverpool John Moores UniversityUK
This edition first published 2019© 2019 John Wiley & Sons Ltd
Edition History1e 2006 Wiley, 2e 2009 Wiley
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Library of Congress Cataloging‐in‐Publication Data
Names: Gunn, Alan, author.Title: Essential forensic biology / Alan Gunn.Description: Third edition. | Hoboken, NJ : John Wiley & Sons, 2019. | Includes bibliographical references and index. |Identifiers: LCCN 2018024347 (print) | LCCN 2018032407 (ebook) | ISBN 9781119141419 (Adobe PDF) | ISBN 9781119141426 (ePub) | ISBN 9781119141402 (pbk.)Subjects: LCSH: Forensic biology.Classification: LCC QH313.5.F67 (ebook) | LCC QH313.5.F67 G86 2018 (print) | DDC 363.25/62–dc23LC record available at https://lccn.loc.gov/2018024347
Cover Design: WileyCover Images: DNA molecules © Svisio/iStock.com, Human skull in concept © Lipowski/iStock.com, Genetic DNA research © Pgiam/iStock.com, Maggot image provided by Alan Gunn
To Sarah, who believes that no evidence is required in order to find a husband guilty.
Introduction
The word ‘forensic’ derives from the Latin forum meaning ‘a market place’: in Roman times, the forum was where people conducted business transactions and some legal proceedings. For many years, the term ‘forensic’ had a restricted definition and denoted a legal investigation. However, nowadays it applies to any detailed analysis of past events, i.e. when one looks for evidence. For example, tracing the source of a pollution incident is now a ‘forensic environmental analysis’, determining past planetary configurations is ‘forensic astronomy’, whilst ‘forensic musicology’ refers to the comparison of two pieces of music in cases of alleged copyright infringement. For the purposes of this book, ‘forensic biology’ is defined broadly as ‘the application of biological sciences to legal investigations’ and therefore covers human anatomy and physiology, viruses to vertebrates and topics from murder to the trade in protected plant species.
Although forensic medicine and forensic science only became specialised areas of study within the last 200 or so years, their origins are traceable back to the earliest civilisations. The first person in recorded history to have medico‐legal responsibilities was Imhotep, Grand Vizier, Chief Justice, architect and personal physician to the Egyptian pharaoh Zozer (or Djoser). Zozer reigned from 2668 to 2649 BC and charged Imhotep with investigating deaths occurring under suspicious circumstances. The Sumerian king Ur‐Nammu (ca 2060 BC) began the first codification of laws with the eponymous ‘Ur‐Nammu Code’, in which penalties of various crimes were stipulated. The first record of a murder trial appears on clay tablets inscribed in 1850 BC at the Babylonian city of Nippur.
In England, the office of coroner dates back to the era of Alfred the Great (871–899), although his precise functions at this time remain uncertain. It was during the reign of Richard I (1189–1199) that the coroner became an established figure in the legal system. The early coroners had widespread powers and responsibilities that included the investigation of crimes ranging from burglary to murder and suspicious death. The body of anyone dying unexpectedly had to be kept for inspection by the coroner, even if the circumstances were not suspicious. Failure to do so meant that those responsible for the body were fined, even though it might have putrefied and created a noisome stench by the time he arrived. It was therefore common practice for unwanted bodies to be dragged away at night to become another village's problem. The coroner's responsibilities changed considerably over the centuries, but up until 1980, he was required to view the body of anyone dying in suspicious circumstances.
Although the coroner was required to observe the corpse, he did not undertake an autopsy. In England and other European countries, dissection of the human body was considered sinful and was banned or permitted only in exceptional circumstances until the nineteenth century. Most Christians believed that after a person died, their body had to be buried ‘whole’. If it was not, the chances of material resurrection on Judgement Day were slight. The first authorised human dissections took place in 1240, when the Holy Roman Emperor Frederick II decreed that a corpse could be dissected at the University of Naples every five years to provide teaching material for medical students. Subsequently, other countries followed suit, albeit slowly. In 1540, King Henry VIII became the first English monarch to legislate for the provision of human dissections by permitting the Company of Barber Surgeons to examine the corpses of four dead criminals per annum. In 1663, King James II increased this figure to six per annum. Subsequently, after passing the death sentence, judges had the option of decreeing the body of the convict to be buried (albeit without ceremony), or exposed on a gibbet or dissected. Nevertheless, the lack of bodies and an eager market among medical colleges created the trade of body snatching. Body snatchers usually left behind the coffin and the burial shroud, because taking these counted as a serious criminal offence – which was potentially punishable by hanging. Removing a body from its grave was merely a ‘misdemeanour’. The modern‐day equivalent is the Internet market in human bones of uncertain provenance. A notorious case arose in 2004 when the body of the eminent journalist Alistair Cooke was plundered whilst ‘resting’ in a funeral parlour in New York. Despite being 95 years old at the time of his death and suffering from cancer, his arms, legs, and pelvis were surreptitiously removed. These were then sold to a tissue processing company for use in surgery or as dental filler. The trade in human bones is legal provided the correct protocols are followed, but it is also highly lucrative and this tempts some people into criminal behaviour.
Although the ancient Greeks performed human dissections, Julius Caesar (102/100–44 BC) has the dubious distinction of being the first recorded murder victim in history to undergo an autopsy. After the assassination, the physician Antistius examined his body. He concluded that although Julius Caesar was stabbed 23 times, only the second of these blows, struck between the first and second ribs, was fatal. The first recorded post mortem to determine the cause of a suspicious death took place in Bologna in 1302. A local man called Azzolino collapsed and died suddenly after a meal and his body quickly became bloated whilst his skin turned olive and then black. Azzolino had many enemies and his family believed that he had been poisoned. A famous surgeon, Bartolomeo de Varignana, was called upon to determine the cause and he was permitted to undertake an autopsy. He concluded that Azzolino died because of an accumulation of blood in veins of the liver and that the death was therefore not suspicious. Although this case set a precedent, there are few records from the following centuries of autopsies to determine the cause of death in suspicious circumstances.
The first book on forensic medicine may have been written by the Chinese physician Hsu Chich‐Ts'si in the sixth century CE but this has since been lost. Subsequently, in 1247, the Chinese magistrate Sung Tz'u wrote a treatise entitled ‘Xi Yuan Ji Lu’ that is usually translated as ‘The Washing Away of Wrongs’, and this is generally accepted as the first forensic textbook. Sung Tz'u would also appear to be the first person to apply an understanding of biology to a criminal investigation. He relates how he identified the person guilty of a murder by observing the swarms of flies attracted to bloodstains on the man's sickle. In Europe, medical knowledge advanced slowly over the centuries and forensic medicine really only started to be identified as a separate branch of medicine in the 1700s (Chapenoire and Benezech 2003). The French physician Francois‐Emanuel Foderé (1764–1835) wrote a landmark 3‐volume publication in 1799 entitled Les lois éclairées par les sciences physiques: ou Traité de médecine‐légale et d'hygiène publique that is recognised as a major advancement in forensic medicine. In 1802, the first chair in Forensic Medicine in the UK was established at Edinburgh University and in 1821 John Gordon Smith wrote the first book on forensic medicine in the English language, entitled ‘The Principles of Forensic Medicine’.
Today, forensic medicine is a well‐established branch of the medical profession. Clinical forensic medicine deals with cases in which the subject is living (e.g. non‐accidental injuries, child abuse, rape), whilst forensic pathology deals with investigations into causes of death that might result in criminal proceedings (e.g. suspected homicide, fatal air accident). Pathology is the study of changes to tissues and organs caused by disease, trauma, toxins, and other harmful processes. Theoretically, any qualified medical doctor can perform an autopsy. However, in practise, at least in the UK, only those doctors who have received specialist training in post‐mortem pathology conduct autopsies.
The majority of deaths are not suspicious, so an autopsy is unlikely to take place. Indeed, even if a doctor requests an autopsy, the relatives of the dead person must give their permission. Some religious groups are opposed to autopsies and/or require a person to be buried within a short period of death so an autopsy may be refused. For example, many Muslims, orthodox Jews and some Christian denominations oppose autopsies. Some doctors are concerned about how few autopsies take place. This is because some estimates suggest that 20–30% of death certificates in the UK incorrectly state the cause of death. The errors are seldom owing to incompetence or a ‘cover‐up’, but result from the difficulty of diagnosing the cause of death without a detailed examination of the dead body.
There are rogue elements in all professions and the GP Dr Harold Shipman murdered over 200 mostly elderly patients over the course of many years. He did this through administering morphine overdoses and then falsifying the death certificates (Pounder 2003). Dr Shipman's victims suffered from a range of chronic ailments and because of their age and infirmities, nobody questioned the certificates he signed. He also falsified his computer patient records. It therefore appeared that the patient suffered from the condition that Dr Shipman claimed caused their death. He sometimes did this within hours of administering a fatal dose of morphine. Ultimately, suspicions were aroused and several of his victims who had been buried were disinterred and autopsied. The findings indicated that although they may have been infirm, they had not died because of disease. Their bodies did, however, contain significant amounts morphine. Providing the tissues do not decay too much, morphine residues are detectable for several years after death. Dr Shipman had therefore, surprisingly for a doctor, chosen one of the worst poisons in terms of leaving evidence behind. Dr Shipman was found guilty of murdering 15 of his victims in January 2000 and subsequently committed suicide whilst in prison.
In England and Wales, when a body is discovered in suspicious circumstances, the doctor issuing the death certificate or the police will inform the coroner. They can then request that an autopsy be performed regardless of the wishes of the relatives. In this case, the autopsy is undertaken by one of the doctors on the Home Office List of pathologists: as of 23 June 2017, there were 36 of them. Each of the Home Office Pathologists covers one of seven regions of England and Wales. The name is a bit of a misnomer because although the Home Office accredits them, the Home Office does not employ them. Scotland has its own laws and the Procurator Fiscal decides whether a death is suspicious and whether one or two pathologists should conduct the autopsy. The situation in Northern Ireland is slightly different again, with pathology services provided by The State Pathologist's department. Other countries have their own arrangements.
Animals and plants have always played a role in human affairs, quite literally in the case of pubic lice, and have been involved in legal wrangles ever since the first courts were convened. There is a long history of disputes over ownership, the destruction of crops and the stealing or killing of domestic animals. For example, Hammurabi, who reigned over Babylonia during 1792–1750 BC, codified many laws relating to property and injury that subsequently became the basis of Mosaic Law. Among these laws, it states that anyone stealing an animal belonging to a freedman must pay back 10‐fold, whilst if the animal belonged to the court or a god, then he had to pay back 30‐fold. Animals have also found themselves in the dock accused of various crimes. In the Middle Ages, several cases are recorded in which pigs, donkeys and other animals were executed by the public hangman following their trial for murder or sodomy. The judicial process was considered important, the animals were appointed a lawyer to defend them, and they were tried and punished like any human. In 1576, the hangman brought shame on the German town of Schweinfurt by publicly hanging a pig in the custody of the court before due process took place. He never worked in the town again and his behaviour gave rise to the term ‘Schweinfurter Sauhenker’ (Schweinfurt sow hangman) to describe a disreputable scoundrel (Evans 1906). Sadly, the phrase has now fallen out of fashion. Today, the owner of a dangerous animal is prosecuted when it wounds or kills someone, although it may still face the death penalty.
During the nineteenth century, a number of French workers made detailed observations on the sequence of invertebrate colonisation of human corpses in cemeteries, and attempts were made to use this knowledge to determine the time since death in murder investigations. Thereafter, invertebrates were used to provide evidence in a sporadic number of murder investigations, but it was not until the 1980s that their potential was widely recognised. Part of the reason for the slow development is the problem of carrying out research that can be applied to real case situations. Pigs, and in particular foetal pigs, are the forensic scientists' usual choice of corpse, although America has a ‘Body Farm’ in which dead humans can be observed decaying under a variety of ‘real life (death?) situations’ (Bass and Jefferson 2003). Leaving any animal to decay inevitably results in a bad smell and attracts flies – so it requires access to land far from human habitation. It also requires protecting the body from birds, dogs, and rats that would drag it away. Consequently, it is difficult both to obtain meaningful replicates and to leave the bodies in a ‘normal’ environment. Even more importantly, in EU countries, these types of experiments conflict with European Union Animal By Products Regulations, which require the bodies of dead farm and domestic animals to be disposed of appropriately to avoid the spread of disease – and leaving a dead pig to moulder on the ground clearly contravenes these.
The use of animals other than insects as forensic indicators has proceeded slowly and that of plant‐based evidence has been slower still. The first use of pollen analysis in a criminal trial appears to have taken place in 1959 (Erdtman 1969). Although not widely used in criminal trials since then, its potential is increasingly recognised. By contrast, the use of plants and other organisms in archaeological investigations has been routine for many years. Microbial evidence seldom features in criminal trials, although this is likely to change with the development of new methods of detection and concerns over bioterrorism.
The use of molecular biology in forensic science has expanded rapidly since the landmark Colin Pitchfork case in 1988, and it is now an accepted procedure for the identification of individuals. Indeed, the use of DNA in forensic science is in danger of becoming a victim of its own success. For example, some commentators have voiced concerns that juries (and lawyers) might consider that DNA evidence is mandatory for a successful prosecution and ignore all other sources of information. In addition, the latest DNA sequencing methods can now detect extremely small amounts of DNA. This means that there is an increased risk of detecting contaminating transfer DNA. In addition, new methods of analysing DNA are revealing information about us that is potentially valuable to law enforcement agencies but also poses privacy issues. On a more positive note, the techniques required to analyse non‐human DNA are advancing rapidly. This will lead to increasing use of evidence from animals and plants in legal proceedings.
A major obstacle to the use of biological evidence in English trials is the nature of the legal system. In a criminal prosecution case, the court must be sure ‘beyond all reasonable doubt’ before it can return a guilty verdict. The court therefore requires a level of certainty that science rarely provides. Indeed, science is based upon hypotheses and a scientific hypothesis is one that can be proved wrong – if one can find the evidence. Organisms are affected by numerous internal and external factors and therefore the evidence based upon them usually has to have qualifications attached to it. For example, suppose the pollen profile found on mud attached to a suspect's shoe was similar to that found at the site of a crime. This suggests a possible association but it would be impossible to state beyond reasonable doubt that no other sites have similar profiles – unlikely perhaps, but not beyond doubt. Lawyers are, quite correctly, experts at exploiting the weaknesses of biological evidence. In particular, it is seldom possible for one to state there is no alternative explanation for the findings or an event would never happen. Within civil courts, biological evidence has greater potential, since here the ‘burden of proof’ is based upon ‘the balance of probabilities’.
Although all biological evidence has its limitations, it is often useful in answering many of the questions that arise whenever a body is found under suspicious circumstances. The first question is, of course, are the remains human? This might be obvious if the body is whole and fresh or even if there is just a skull but sometimes there may be no more than a single bone or some old bloodstains. Assuming that the remains are human, biological evidence can also help to answer the subsequent questions (Table I.1).
Table I.1 Questions arising when a body is found in suspicious circumstances.
Are the remains of human origin? Who is the victim? What was the cause of death? How long ago did the victim die? Did the victim die immediately or after a period – and if so, how long? Did the person die at the spot where their body was found? Did the person die of natural causes, suicide, an accident, or a criminal act? If the person was killed as a result of a criminal act, who was responsible?
Similar questions arise in wildlife crime (e.g. killing of/trade in protected species), neglect of humans and domestic animals, mis‐selling of animal products, and food contamination. This book intends to demonstrate how an understanding of biology can answer all these questions. It is designed for undergraduates who may have a limited background in biology and not the practicing forensic scientist. I have therefore kept the terminology simple, whilst still explaining how an understanding of biological characteristics provides evidence. Descriptions of potential sources of biological evidence and tests continue to grow at a bewildering rate. Therefore, it is essential to distinguish between approaches that will be useful in the real world and those that will never proceed further than the laboratory pilot study. To be truly useful any test/source of evidence must be accurate, simple, affordable, and deliver results within an acceptable period (Table I.2). With such a large subject base, it is impossible to cover all topics in depth and readers wishing to identify a maggot or undertake PCR analysis should consult one of the more advanced specialist texts or review articles mentioned at the start of each chapter. Where information would not otherwise be easily accessible to undergraduate students, I make use of web‐based material, although the usual caveats apply to such sources.
Table I.2 Characteristics of an ideal forensic test.
Accurate:
The results must stand up to intense scrutiny in court.
Sensitive:
Many forensic samples are extremely small and are finite (i.e. one cannot collect more material once it used up).
Specific:
If the test also cross‐reacts with other materials, then its accuracy will be compromised.
Quick:
Investigations must not drag on. If there is a chance that a criminal might offend again, they must be apprehended and charged as soon as possible. It is also unfair to keep a suspect in a state of anxiety and/or deprive him/her of his/her liberty for long periods whilst time‐consuming tests are conducted.
Simple:
The more complex a test becomes the more opportunity there is for mistakes to occur. It also becomes expensive to train people to conduct the tests.
Reliable and repeatable:
It is essential that a test is replicable by workers at other laboratories.
Affordable:
Financial considerations are important. One cannot employ an exceedingly expensive test on a routine basis.
Equipment and reagents are readily available:
The effectiveness of a test is compromised if equipment cannot be used through lack of spare parts or the reagents it requires are difficult to obtain.
This is the third edition of Essential Forensic Biology and although the basic structure is similar, all the chapters have been re‐written, updated, and include many new illustrations. Some of the chapters in the second edition are now divided into two, in order to provide greater focus and in‐depth coverage of topics. There is also a new chapter on Wildlife Forensics. This is in recognition of the scale of the problem and the consequences it is having on both the environment and human societies. The illegal trade in wildlife is a global problem and often involves other illegal activities and organised criminal gangs. There is also an expanded Companion Website. This includes multiple choice questions (and answers) and short answer questions associated with each chapter. In addition, there are interpretative questions that require the reader to utilise information gained from several chapters. The website now includes numerous photographs that could not be included in the book without increasing its size and cost. I provide some ideas for project work that do not require access to complex laboratory facilities. Because the usefulness of biological material as forensic evidence depends on a thorough understanding of basic biological processes and the factors that affect them, there is plenty of scope for simple projects based upon identifying species composition or that measure growth rates. Obviously, for the majority of student projects, cost, time, and facilities are serious constraints. Although DNA analysis is extremely important in many aspects of forensic biology, it can be expensive and requires specialist equipment. Similarly, the opportunities to work with human tissues or suitably sized dead pigs may not exist. However, one can undertake worthwhile work using the bodies of laboratory rats and mice or meat and bones bought from a butcher as substitute corpses with plants and invertebrates as sources of evidence.
At the start of each chapter, I list a series of ‘objectives’ to illustrate the material covered. These take the form of examination essay questions, so that the reader might use them as part of a self‐assessment revision exercise. I divide the book into a series of conventional chapters but because topics are inter‐related, the reader will find certain subjects picked up, put down, and then returned to later. This is also a good way of learning, since it is better to take in bite‐sized chunks of information and return to them frequently, rather than attempt to grasp all aspects of a topic in a single sitting. The book begins with a discussion of how the human body decays and how one discovers and recovers a dead body. There is then an in‐depth consideration of how one conducts DNA and RNA analysis and how this contributes to forensic biology. This area of science is advancing at an incredible speed, but in the process of providing a wealth of information that can help solve crimes, it is also throwing up serious practical and ethical issues. The book then deals with body tissues and fluids as forensic indicators. We then consider how wound analysis can help establish whether a suspicious death was a result of an accident, suicide, or homicide. Film and TV depictions of forensic pathology often suggest a degree of certainty when diagnosing the cause of death that is not always possible. This chapter emphasises the importance of proceeding cautiously and keeping an open mind. There is then a consideration of the animal kingdom as forensic indicators. This begins with the invertebrates. These are used primarily to determine the minimum time since death, although their importance in other scenarios is also considered. We then deal with the vertebrates and, as mentioned previously, there is now a new chapter on wildlife forensics.
The chapter on plants as forensic indicators is now longer because until recently this source of forensic evidence was often overlooked. In addition, there is now more information on plant poisons, such as ricin, because of the concern about their use by terrorists and hostile governments targeting unwelcome critics. There is also more information on the illegal trade in plants, because it is equally important (and profitable) as illegal animal trafficking but seldom receives attention in the popular press. The final chapter on microbes and viruses now includes a detailed consideration of the prospects of microbiomes as forensic indicators. To its supporters, microbiome analysis offers the prospects of revolutionising our understanding of many disease processes and the prospects of new therapeutic approaches. As a spin‐off from this, microbiome analysis is increasingly proposed as a new means of answering forensic questions such as the time since death, individual identity, and geographical origin. This chapter considers the strengths of these claims. There is also new information on the transmission of a disease as a criminal act and the use of microbes and viruses in bioterrorism.
Acknowledgements
Thanks to Sarah and to all of the academic and technical staff at the School of Natural Sciences & Psychology, Liverpool John Moores University who helped me along the way.
About the Companion Website
The companion website for this book is at
www.wiley.com/go/Gunn/Forensic
The website includes:
PPTs of all figures in the book
MCQs as per 2e BCS
Projects
Short Answer Questions
Interpretative Questions
Interpretative Questions Answers
Website Images
Scan this QR code to visit the companion website.
Part IDecay and the Discovery and Recovery of Human Remains
1The Decay of Human Bodies
OBJECTIVES
Compare the chemical and physical characteristics of the different stages of decomposition.
Explain how a body's rate of decomposition is affected by the way in which death occurred and the environment in which it is placed.
Compare the conditions that promote the formation of adipocere and of mummification and how these processes preserve body tissues.
1.1 Introduction
The time before a person dies is the ante‐mortem period, whilst that after death is the post‐mortem period. The moment of death is the ‘agonal period’ – the word being derived from ‘agony’, because it used to be believed that death was always a painful experience. Either side of the moment of death is the peri‐mortem period, although there is no consensus about how many hours this should encompass. It is important to know in which of these time periods events took place in order to determine their sequence, the cause of death, and whether or not a crime might have been committed. Similarly, it is important to know the length of the post‐mortem period, referred to as the post‐mortem interval (PMI). This is because by knowing exactly when death occurred it is possible, among other things, to either include or exclude the involvement of a suspect. The study of what happens to remains after death is ‘taphonomy’ and the factors that affect the remains are ‘taphonomic processes’. Thus, burning, maggot feeding, and cannibalism are all examples of taphonomic processes.
When investigating any death, it is essential to keep an open mind as to the possible causes. For example, if the partially clothed body of a woman is found on an isolated moor, there are many possible explanations other than she was murdered following a sexual assault. First, she may have lost some of her clothes after death, through them decaying and blowing away or from them being ripped off by scavengers. Second, she may have been a keen rambler who liked the open countryside. Most people die of natural causes and she may have suffered from a medical condition that predisposed her to a heart attack, stroke, or similar potentially fatal condition whilst out on one of her walks. Another possibility is that she may have committed suicide: people with suicidal intent will sometimes choose an isolated spot in which to die. Another explanation for the woman's death would be that she had suffered an accident, such as tripping over a stone, landing badly, and receiving a fatal blow to her head. And, finally, it is possible that she was murdered. All of these scenarios must be considered in the light of the evidence provided by the scene and the body.
1.2 The Stages of Decomposition
After we die, our body undergoes dramatic changes in its chemical and physical composition and these provide an indication of the PMI. The changes also influence the body's attractiveness to detritivores (organisms that consume dead organic matter) and their species composition and abundance. These also act as indicators of the PMI. Furthermore, the post‐mortem events may preserve or destroy forensic evidence, as well as bring about the formation of artefacts. For example, the discharge of bloody fluids from the mouth and nose or the bluish discoloration of the skin, which are perfectly normal consequences of decay, can be mistaken for signs of assault or poisoning. An understanding of the decay process, and factors that influence it, is therefore essential for the interpretation of dead human and animal remains.
Animal decomposition in terrestrial environments can be divided into four stages: fresh, bloat, putrefaction, and putrid dry remains. However, these stages merge into one another and it is impossible to separate them into discrete entities. Indeed, bloat results from the process of putrefaction and therefore is dealt with as a sub‐section of putrefaction in this chapter. In addition, a body seldom decays in a uniform manner. Consequently, part of the body may be skeletonised, whilst another part retains fleshy tissue.
1.2.1 Fresh
Once the heart stops beating, the blood pressure drops and blood is no longer moved through the body. The blood within the vessels therefore settles under gravity to the lowermost dependent regions. Consequently, shortly after death, the skin and mucous membranes appear pale. Once the circulation ceases, tissues and cells no longer receive oxygen and nutrients and they begin to die. Different cells die at different rates, so, for example, brain cells die within 3–7 minutes, while skin cells can be taken from a dead body for up to 24 hours after death and still grow in a laboratory culture. Contrary to folklore, human hair and fingernails do not grow after death, although shrinkage of the surrounding skin makes it seem as though they do.
1.2.1.1 Temperature Changes
Because normal metabolism ceases after death, our body starts to cool in a process known as algor mortis: literally, the coldness of death. For many years, measurements of body temperature were the principal means of determining the PMI. However, the technique suffers from a variety of shortcomings. To begin with, the skin surface usually cools rapidly after death and the mouth often remains open. Therefore, measurements recorded from the mouth or under the armpits would not reflect the core body temperature. In living persons, one way of determining core body temperature is with a rectal thermometer. However, this approach is not always appropriate in forensic cases. This is because inserting a rectal thermometer often requires moving the body and removing the clothing. This potentially interferes with evidence collection in cases where anal intercourse before or after death occurred.
Nowadays, the body temperature of living humans and many domestic animals is often determined from the temperature in the external auditory canal, measured using a custom‐designed electronic digital ear thermometer. This has the advantage of being quick, non‐invasive, and does not risk cross contamination or breakage of the thermometer in the body. The external auditory canal temperature correlates well with the brain temperature and it is useful for recording the temperature of dead bodies in hospital settings (Baccino et al. 1996). Unfortunately, in forensic scenarios, there are often complications that make the measurement of the ear temperature either difficult or the interpretation of the results questionable (Rutty 1997); for example, if the body is submerged or water enters the ear canal from rain or condensation, if there is bleeding into the ear canal following a skull fracture, and if there is traumatic damage to the ears from blows to the head.
A second major problem with using body temperature as a measure of the PMI is that the rate of cooling depends upon a host of complicating factors. These start with the assumption that the body temperature at the time of death was 37 °C. In reality the body temperature may be higher (e.g. owing to infection, exercise, or heat stroke) or lower (e.g. hypothermia or severe blood loss). In addition, the rate of temperature loss depends upon numerous factors (Table 1.1). For example, subcutaneous fat acts as an insulator that reduces the rate at which heat is lost from the body. Adult women tend to have a higher fat content than men, and therefore the bodies of a woman and a man of the same weight cool down at different rates. Similarly, the body of a fat man who dies inside a car on a hot sunny day may not lose heat to any appreciable extent; indeed, his body temperature may even increase.
Table 1.1 Factors affecting the rate at which a body cools after death.
Factors that enhance the rate of cooling
Small body sizeLow fat contentBody stretched outBody dismemberedSerious blood lossLack of clothesWet clothesStrong air currentsLow ambient temperatureRain, hailCold, damp substrate that conducts heat readily (e.g. damp clay soil)Body in cold waterDry atmosphere
Factors that delay the rate of cooling
Large body sizeHigh fat contentFoetal position (reduces the exposed surface area)Clothing – the nature of clothing is important because a thin, highly insulated layer can provide more protection than a thick poorly insulated material.Insulated covering (e.g. blanket, dustbin bags, paper, etc.)Protection from draughtsWarm ambient temperatureWarm microclimate (e.g. body next to a hot radiator)Exposed to the sunInsulated substrate (e.g. mattress)High humidity
Various formulae relate body temperature to the length of time since death, but these are mostly too simplistic to be reliable. Clauss Henßge designed a sophisticated nomogram that accounts for body weight and environmental temperature and allows application of corrective factors according to the individual circumstances of the case (Henssge and Madea 2004). A nomogram is a graphical calculator that usually has three scales (Figure 1.1). Two of these scales record known values (rectal and environmental temperature) and the third scale is the one from which the result is read off (time since death). Unfortunately, even this approach has limitations – for example, it is not reliable if the body was left exposed to the sun or if there is reason to believe that it was moved after death. In the latter situation, the body experiences at least two different environments and therefore spends time cooling at two or more rates. This is not to say that temperature measurements are of limited value, but one should be aware of possible complicating factors.
Figure 1.1 Clauss Henßge's nomogram for the determination of time since death from body temperature.
Source: Reproduced from Henssge and Madea (2004), © Elsevier, with permission.
The nomogram works as follows: (a) One draws a straight line between the rectal temperature and the ambient temperature. In this case, one draws a line from 27–15 °C. (b) The ‘standard’ is a naked body lying in an extended position in still air and therefore ‘corrective factors’ are applied for any situations other than this. Henssge and Madea (2004
