Forensics

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Forensics Page 9

by Val McDermid


  Today, Dick Shepherd is the leading forensic pathologist in the UK. But he is adamant that he is no celebrity courtroom performer – and nor would he want to be, even though the roll call of some of his autopsy subjects is remarkable. From Princess Diana and Jill Dando to victims of the 9/11 attacks in the US, he has investigated some of the most notorious deaths of recent years. To him, every case is the same: an autopsy is supposed to be ‘a non-judgemental, scientific, acquisition of facts’, no matter who the victim is.

  What gets Dick Shepherd up in the morning is the living, not the dead. ‘I’m fascinated by the interlinking – working with the police, the courts and with other people. Seeing problems, understanding them, interpreting them and providing that information to others. I have to separate myself from the destructive things that I do and remember that I am doing it for the families of the dead. If they understand what has happened it doesn’t help them in any practical way, but if there are points of truth they can fix on them, and achieve closure. Forensic science has gone wrong when people haven’t been truthful, sometimes because they have hidden the truth in the hope of not distressing families. It never works.’

  It’s up to the police to make the tricky call about how much a pathologist should know of a case before the first crucial examination of a body. If the pathologist knows too much it might bias the autopsy. If he knows too little he might overlook something important. And, as Dick Shepherd explains, ‘If the filtering is done by others they may not give us a critical bit of information. Then when it suddenly pops out in court, it can lead to an “Oh, cor blimey” moment. The lawyer asks, “If you had been told this would you have formed another opinion?” “Yes, I would.” “Oh, thank you, Dr Shepherd.” Lawyer sits down with smug smile on face.’ And the prosecution winces.

  One of the reasons Spilsbury so rarely had to witness a defence lawyer’s smug smile was that he almost invariably knew a great deal of the background to his cases. Nowadays, when Dick Shepherd gets a call from the police or the coroner’s office, he is seldom summoned to the crime scene but rather to the mortuary. Various other scientists with specialisms such as blood spatter and DNA analysis do much of the crime scene evidence gathering that forensic pathologists used to be responsible for. At the scene of death, junior CSIs bag up the body to prevent trace evidence falling from it, such as hair, fibres and dirt, and to protect it from contamination.

  When he does go – and ‘sometimes it is really useful to, not so much to do any specific examinations but to interpret the scenario’ – Dick observes body position and proximity to other evidence such as weapons, fingerprints, points of entry and escape. He has to be very careful not to lose or contaminate evidence by touching or moving the body more than is absolutely necessary. In a recent case of his, the police believed a lady found at the bottom of her stairs had taken a tumble. Dick went along to see ‘where she was lying, how she was lying, if she had possibly been moved. When I did the autopsy I found injuries that I thought were caused by her coming down the stairs and banging into things. Because I’d gone to the scene I could later explain the layer of grazes on her side as being where she had gone around a corner.’

  Detectives always want an estimated time of death. That’s information that can shake, break or confirm a suspect’s alibi. The longer a body has been dead, the harder it is to estimate with much accuracy when death occurred; the narrower the estimate, the more useful it is to the investigation.

  The first thing a pathologist like Dick Shepherd does when examining a corpse is to take its rectal temperature, unless there is reason to suspect sexual assault. In such cases, he stabs the thermometer into the abdomen. It was once thought that bodies lose heat at a constant 1°C per hour until they reach ambient temperature. So, for example, if a person dies with the average body temperature of 37°C in a 20°C room, there will potentially be a 17-hour window when the time of death can be roughly estimated. But research has shown significant variables: a thin body cools faster than a fat one; the larger the surface area, the faster the cooling process; whether the body is sprawled or curled up will have an impact; clothing will affect the cooling; shade or sunlight; in the shallows or beside a river. Even so, an early and careful reading can be a useful starting point and pathologists can factor in variables like ambient temperature and body weight using a graph with multiple axes called a nomogram.

  The next phenomenon that interests Dick is rigor mortis – the macabre reason why dead bodies are known as ‘stiffs’. The symptoms of rigor are useful to the pathologist for about two days after death because of a recognised cycle. At first a body relaxes completely, then after three or four hours the small muscles of the eyelids, face and neck begin to stiffen. Rigor progresses downwards, from head to toe towards the larger muscles. After twelve hours the body is completely rigid and will stay fixed in the position of death for around twenty-four hours. Then the muscles gradually relax and stiffness goes away in the order in which it appeared, starting with the smaller muscles and progressing to the larger ones. After a further twelve hours or so all the muscles reach a state of complete relaxation.

  But even a process as well documented as rigor mortis is a very imperfect indicator of time of death. The hotter the ambient temperature, the faster each step of the cycle occurs. Also, bending and stretching a corpse breaks up its muscle fibres and eliminates rigor, a piece of information that murderers have been known to employ to confound the investigation.

  Rigor mortis is followed by the least majestic stage of the body’s time on earth. ‘Putrefaction’ may not be a loveable phenomenon, but forensic pathologists need to be on intimate terms with it to do their jobs properly. First the skin around the abdomen turns greenish as the bacteria in the lower intestine begin a process of ‘self-digestion’. As bacteria grow throughout the body, breaking down proteins into amino acids, they produce gases and cause the body to bloat – starting with the features of the face, where the eyes and tongue begin to protrude. Next, a web-like pattern of blood vessels appears as marbling on the skin because the red blood cells break down and release haemoglobin. Gases continue to swell the abdomen until they escape, sometimes explosively, and produce a vile smell. The body has turned greenish-black by now, as fluids drain from the nose and mouth, and the skin falls away like ‘a giant rotting tomato’.

  All the while, and aided by ‘self-digestion’, the internal organs have been liquefying, starting with the digestive organs and the lungs, and then the brain. Flies have laid eggs on the body’s points of entry, such as the eyes, mouth and open wounds, and maggots have been tearing continuously at the flesh.

  Scientists are continually studying and refining the various different ways of measuring time since death. However, as forensic anthropologist Sue Black explains, this doesn’t always simplify matters. ‘The more information we get, the more we realise just how difficult it is. No two bodies will decompose in the same way, and at the same rate. You can have two bodies that are literally six feet apart and they will decompose in entirely different manners. It could be the amount of fat on the body. It could be the drugs they were taking, or the medication. It could be the type of clothing they’re wearing. It could be that one has a particular odour that is more attractive to flies than the other. Absolutely anything.’

  One way to try and combat the headache of variables is to develop new tools. That’s what the Anthropological Research Facility at the University of Tennessee has been doing for years. ‘The Body Farm’, as it’s better known, was set up in 1981 by William Bass to research putrefaction. It was the first institution to develop the systematic study of human decomposition and how bodies interact with the environment. More than 100 people donate their bodies to the Body Farm every year, to be placed in different settings and left to rot. Researchers have worked out a general rule of thumb: one week exposed above ground equals eight weeks below and two weeks in water.

  Arpad Vass, Associate Professor of Forensic Anthropology at the University of Tennessee,
is developing a new method for estimating time since death. ‘Decomposition Odour Analysis’ hopes to identify the 400 or so distinct vapours that a body gives off at different stages of its decomposition. Understanding when these vapours are given off, in a variety of settings, and measuring them in a corpse, could provide a more accurate time of death than has so far been possible.

  Findings from research facilities such as the Body Farm trickle into the world of practical forensics through journals and monographs, and arm pathologists with knowledge that they can use to give better evidence to criminal investigations. Pathologists use that knowledge most usually in a morgue or a hospital, locked in the intense focus of autopsy. How and why did the person die? Was it suicide, murder, an accident, old age, or is it impossible to tell? There are seldom straightforward answers. A bullet that has passed through someone’s head could have been shot suicidally, murderously or accidentally. The scope of a forensic pathologist’s curiosity is very broad when he enters the morgue. It gradually narrows its focus to the small details, before broadening out again to incorporate those details in a conclusion. The general steps of an autopsy have changed little since the beginning of last century.

  When the body arrives in the morgue Dick Shepherd is ready to photograph it. An assistant takes the bag the body was stored in for transportation and searches it for trace evidence. Dick removes the subject’s clothes, which he photographs, bags and documents. Then he takes biological samples, plucking hair, scraping fingernails, swabbing sexual organs. Only now does he carefully take the fingerprints; prying open fingers to take prints can jeopardise small bits of trace evidence clenched in a fist closed by rigor.

  Dick then washes the body and documents every scar, birthmark, tattoo and unusual physical feature he can find. ‘Every pathologist has a different route,’ says Dick. ‘I start at the head and I always do the left-hand side first. So I do head, chest, abdomen, back, left hand, right hand, left leg, right leg. As I go around, injuries are all documented and photographed. I have to say my heart sinks now when it’s a pub fight and there’s 970 2 cm bruises. Can’t I just say there were lots of bruises on the legs? No.’ In less clear-cut cases the rigorous style encouraged by the documenting process can prove invaluable, as illustrated by another British wife who died in a bath.

  At 11 p.m. on 3 May 1957, Kenneth Barlow, a nurse from Bradford, phoned 999 to say that he had found his wife unconscious in the bath. He explained that he had pulled her out and spent a long time trying to resuscitate her, and that she had been suffering from vomiting and fever that evening. Investigators were suspicious when they discovered two used syringes in the kitchen. Kenneth explained that he was using them to treat an abscess he had with penicillin. Tests confirmed the presence of penicillin.

  But pathologist David Price remained suspicious. During the autopsy he searched every inch of Mrs Barlow’s skin with a magnifying glass. Eventually he found two tiny holes consistent with injection needles, one on each of Mrs Barlow’s buttocks. The symptoms that Kenneth had said his wife was suffering from were those of hypoglycaemia (low blood sugar), which made David Price suspect that he had injected his wife with a lethal dose of insulin. There were no tests for insulin at the time, so Price took tissue from around the injection points on Mrs Barlow’s buttocks and injected it into mice. They quickly died of hypoglycaemia. Barlow was found guilty of murder and given a life sentence.

  After the meticulous external scrutiny, the internal examination begins. The pathologist is looking both for internal injuries and any medical condition that might have caused the person to die naturally. Dick Shepherd cuts open the body in a ‘Y’ shape from both shoulders down to the groin, sawing open the ribs and collarbone and removing the breastplate, to reveal the heart and lungs. He inspects the neck, looking out for things like broken cartilage, which might indicate strangulation. He then takes out the organs individually (like the liver) or in groups (like the heart and lungs), examines their surfaces, and makes cuts to examine them internally. He preserves samples of the organs. ‘The Home Office now insist that we do microscopic examinations of all of the major organs on every case, even when it’s an 18-year-old who’s been hit by a baseball bat on the top of the head.’ Better safe than sorry, for which we should all be grateful. He then sends those samples off to the laboratory. Next Dick makes an ear-to-ear incision over the top of the head and peels back the scalp. Now he can saw away a section of the skull and look at the brain in place before removing it for a closer examination.

  Finally, Dick sews up all the incisions he has made in the organs, places them carefully back in the body, and stitches up his initial ‘Y’ incision. Afterwards he talks to detectives and to other forensics experts, pools ideas about what looks suspicious or needs to be followed up, and feeds back into the inquiry. Very often there will be a second autopsy, so that another pathologist can check Dick’s findings. Once all the reports have come in from the experts – bone pathologists, neuropathologists, paediatric radiologists – Dick writes his report for the coroner.

  In some extreme situations more than one autopsy will follow Dick’s. On 23 August 2010, the police found a red North Face bag in the bath of a flat in Pimlico, London. It belonged to Gareth Williams, a Welsh maths prodigy who had been working as a codebreaker for MI6, and its zips were fastened with a padlock on the outside. When the police prised the padlock open they found the naked, decomposing body of 31-year-old Gareth folded inside.

  The police regarded the death as suspicious. Gareth Williams’ family were convinced that M16 or another secret service was involved in the death, as Williams had been working with the FBI as part of a team attempting to penetrate hacking networks.

  Dick Shepherd was one of three pathologists who performed autopsies, and who all agreed that Williams had been dead for about seven days. Whilst they found no signs of strangulation or physical trauma, it was difficult for them to determine the cause of death because the body had decomposed so quickly: the bag had been found in the summer, and all the radiators in the house had been left on maximum. Toxicologists found no signs of poisoning but, because of the body’s condition, they couldn’t rule it out. Suffocation seemed most likely.

  The autopsies revealed small abrasions on the tips of Williams’ elbows, which might have resulted from him moving his arms inside the bag, possibly in an attempt to escape. Dick Shepherd summed up the situation: ‘Once the lock was placed on it there was no possibility of getting out of that bag. The question is: did he place the lock there or did another?’

  Peter Faulding, an ex-military reservist who specialised in rescuing people from confined spaces, told the inquest in May 2001 that he had tried 300 times to lock himself into an identical 81 cm by 48 cm North Face bag, and failed to do so. He said that even Harry Houdini ‘would have struggled to lock himself in the bag’. Another expert had tried and failed a further 100 times.

  But Dick Shepherd felt that Williams had suffocated, and was ‘more likely than not’ alive when he entered the bag. He reasoned that, because Williams was hunched into such a tight ball when he was found, and because of how ‘floppy’ a body is before rigor mortis sets in, it would have been very tricky for someone else to stuff him inside it. No expert offered to test this theory. It was also revealed at the inquest that DNA found on Williams’ finger during his first autopsy did not come from a mysterious Mediterranean couple that the police had been pursuing for a year. An employee at LGC, the forensic company which was analysing samples, had typed the wrong DNA details into a database. The DNA in fact belonged to one of the CSIs who had been at the scene. LGC expressed ‘very deep regret’ to the Williams family for the mistake.

  Twenty thousand pounds-worth of designer women’s clothes had been found at Williams’ flat, along with women’s shoes and wigs. Investigators had also found pictures of drag queens and evidence that he had been browsing self-bondage websites and sites about claustrophilia – the love of enclosure – days before his death.

  T
he coroner, Fiona Wilcox, ruled that, though there was not enough evidence to give a verdict of unlawful killing, it was probable that the death was unnatural, that someone else had locked him in the bag and placed it in the bath, and that he was alive when he entered it. She added that there was no evidence to suggest that Williams was a transvestite ‘or interested in any such thing’.

  Days after the verdict, a 16-year-old girl and a 23-year-old journalist separately attempted to lock themselves into identical North Face bags: they climbed in, drew their legs up, pulled the zippers nearly shut, poked their fingers through the gap, and closed the padlock. They then tensed their bodies, and the zip sealed itself up. The journalist, who was of a similar build to Gareth Williams, repeated the trick a number of times until she could do it in three minutes.

  Peter Faulding didn’t think much of these stunts. ‘None of my conclusions are wrong. A young girl zipping a bag doesn’t discredit this inquiry whatsoever. We were fully aware of other methods of being able to lock the bag but she or nobody could achieve it without leaving her DNA or trace on the bath and that’s the key to this.’

  Dick Shepherd continues to disagree. ‘I’ll never convince the coroner. She was furious with me; the word “incandescent” springs to mind. One of the strongest things that makes me feel he was on his own is that he lived a solitary existence, wearing women’s clothes, working intensely, and being a mathematics geek – forget the pathology, the psychology is not right.’

  In 2013, the Met Police held an internal investigation because the coroner had indicated that MI6 staff might have been involved. By November Scotland Yard had the investigation’s verdict: it was probable that Williams had died alone, as a result of accidentally locking himself inside the bag. Dick Shepherd’s view had been vindicated.

 

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