by Sue Black
Now Mary had indeed gone missing, something to which her husband did not alert the police for five days. In an interview he stated that she had come home from work that day, they’d had a blazing row and she had stormed out. She had, he said, not been intending to return until she had calmed down. He thought she might have gone down to London to stay with one of their grown-up children. Needless to say, she had not.
A scene-of-crime team took control of the family home. They found some blood in the bathroom, which would eventually be DNA-matched to Mary, and when they put an endoscope down the U-bend of the bath, they recovered a small piece of chipped tooth enamel. This was not, of course, by any means enough to suggest that she was dead. She might have tripped going into the bathroom and cracked her chin on the side of the bath. An everyday fall could easily explain both the presence of her blood and the fragment of tooth enamel.
The SOCOs then checked out the kitchen, where they found some blood around the door of the washing machine. This, too, would be confirmed in due course as Mary’s. From the filter of the machine they retrieved what they believed might be a small piece of bone. Before sending this for DNA analysis, they needed an anthropologist to have a look at it and to tell them, if possible, whether it was bone, whether it might be human and, if it was, where on the body it might have come from.
We have to be very careful about the order in which small pieces of evidence are analysed. It is important that all non-destructive forensic tests are completed first, before irreversible changes are caused in the evidence. This chip of bone, if that was what it was, was only about a centimetre long and half as wide. Testing it for DNA would entail grinding it down and all but destroying it. Trying to identify the bone anatomically was critical as a potential murder charge might hinge on it. It is quite possible to live without some bits of bone, whereas finding others outside the body would indicate that the person they belonged to is very probably dead.
The police brought the fragment to my laboratory and we all sat around the table while my colleague and I peered through magnifying lenses to try to figure out what we might be looking at. It was so delicate that we were loath to pick it up lest we damage it further. Situations like this are horribly stressful because we have to lay bare our thought processes in front of the officers in the room. What you think the bone may be when you start your deliberations is often not what you decide it is most likely to be at the end. Having to arrive at your conclusions out loud, via all the inevitable dead ends and red herrings, makes you worry what the police must think of you and your expertise.
But we must follow a rigorous process of evaluation, elimination and confirmation of identity. There is no alternative to experience and honest academic debate. Sadly, we cannot always conjure a Sherlock Holmes moment by holding up a shard of bone and exclaiming: “Aha! If I am not mistaken, Watson, this is a fragment of the left superior articular facet of the third thoracic vertebra from a woman twenty-three years of age who walked with a limp!” It is like having a single piece of a unique, 1,000-piece jigsaw puzzle. Because no two anatomical jigsaws are ever the same. Does it have edges? Can you see a pattern? Does that pattern occur in more than one place?
On this occasion, what we were clear about from the start was that the fragment was indeed bone, and that it came from the skull. It had a thin shell with a smooth outer covering and an inner surface that was slightly convoluted, with a ridge running across it. There was simply no other part of the body we could think of where this combination of characteristics would occur.
Now the puzzle became a process of positional elimination. It could not have come from the major bones of the vault, or skull cap, the upper part of the neurocranium, because this is composed only of diploic bone. As there was no diploic bone present, it had to be from the sides, the base or the face. As convolutions on the inner surface form in response to the sulci and gyri (ridges and valleys) of the cerebral hemispheres of the brain, we narrowed down our options to three possible sites: the orbital plate of the frontal bone (the roof of the eye socket), the squamous part of the temporal bone (at the side of the head above the ear) or the greater wing of the sphenoid bone (the temple area behind the eye, and in front of the ear, that you instinctively massage when you have a headache).
We decided it was too thick to be from the roof of the eye socket. The second proposition we ruled out because there is no corresponding ridge on that part of the temporal bone. No, the last and only place it could have come from was the sphenoid bone. This is a partial vault bone, without diploic structure, which shows indentations of the cerebral hemisphere on the internal surface and carries a ridge marking its junction with the frontal bone. This placement felt comfortable and defensible and we believed we had eliminated all other reasonable possibilities. Our debate had taken an hour and the police were clearly getting rather bored with us and our unintelligible anatomical babbling.
Finally, we had to determine whether it was from the right side or the left. If we were correct, it could only have come from the left, or the positioning and orientation of the ridge would have been reversed. Running close to this thin area of bone are very large blood vessels (middle meningeal vessels), and if this part of the skull was fractured, with this piece of bone extruded, then it was fairly safe to assume that Mary was no longer alive.
This, however, was a decision for the pathologist. He agreed with our conclusion, although he admitted that he couldn’t comment on the identification of the bone fragment as it was beyond his anatomical knowledge. Far from being pleased by this tip of the hat to the depth of our own anatomical experience, we interpreted the pathologist’s response as a warning bell. It meant we were likely to be called into court if the case went to trial because identification of the bone fragment would probably be crucial to the prosecution’s case. And the procurator fiscal had confirmed that this was now a murder investigation.
The chip of bone went off for DNA testing and it was confirmed that it belonged to Mary. The husband changed his story. He said that his wife had come home and the row between them had got heated. He claimed that she had been holding a knife, because she was making sandwiches, and that he was fearful she was going to hurt him with it. He grabbed her by the hand and pushed her away, but she fell through the kitchen doorway and tumbled down a flight of steps, hitting her head on the concrete floor at the bottom. There was, he averred, blood and brain splattered everywhere. This, I might add, is not necessarily what happens when a head comes into contact with a concrete surface, and indeed no significant amount of blood had been found at the foot of the steps.
He said there was a large pool of blood coming from a wound on the left side of her head, near her ear. He realized that she was dead and so he carried her into the bathroom and laid her in the bath. He then cleaned up the house, wrapped her in plastic sheeting and put her into the boot of his car. At two o’clock the following morning, he drove off to dispose of the body. This was one part of his story the police were able to corroborate, as Mary’s blood was found in the boot and his car was picked up by traffic cameras. He told them that he dumped her body into a local, fast-flowing river. To this day, she has never been found.
He had put his bloody clothes in the wash, unwittingly transferring that splinter of Mary’s sphenoid bone into the machine with them. It is lucky that he did not run it at a hot temperature with a biological detergent, or we may not have been able to retrieve any DNA.
Had that been the case, it would have been much more difficult for the prosecution and forensic science to prove that the bone was Mary’s. You would be forgiven for wondering who on earth else it could have belonged to, but of course, in the interests of a fair trial, our legal system requires that the burden of proof lies with the prosecution, and all the defence must do is introduce reasonable doubt.
As I’d feared, I was summoned to appear in court, where my intimate knowledge of the anatomy of the human body, even as represented by a mere chip of bone, was inevitably going to be
tested robustly. The courtroom is an alien environment to a scientist. We can only answer the questions we are asked, and if the right questions are not forthcoming, it can be a gruelling and frustrating experience. In Scotland you cannot sit in the courtroom throughout the proceedings and therefore you go in cold, with no forewarning of the legal strategies in play, or of any evidence that has already been presented or is yet to be heard.
First the prosecution, in the shape of an advocate depute I had never met, began his evidence in chief by asking, on behalf of the Crown, about my credentials. I was then permitted to give my evidence and questioned on how I had reached my opinion. When you are appearing for the Crown, this is often the easiest part of the day as the prosecution has no desire or intention to challenge your testimony unless it assists their case in some way to do so. It was over in around an hour or so and much of that time was spent on satisfying the court that I was suitably qualified to give opinion evidence.
It is really important that the opinion you present in court is based solely on your specific area of experience and knowledge and that you do not stray outside your field of expertise. My evidence that day was simple. I believed the fragment to be bone, and I believed it to come from the left greater wing of the sphenoid bone. I could not comment on whether the individual to whom it belonged was still alive. I could not comment on whether the fragment belonged to Mary. I could not confirm how long the fragment had sat in the filter of the washing machine. I could not comment on how it had got there.
As judges and juries normally like to break for lunch quite promptly, I calculated that at least I would have to suffer no more than two or three hours of cross-examination by the defence. The defence QC was a man I know very well and respect enormously, but that doesn’t necessarily make our court encounters a convivial affair. He is very good at his job and, although he denies it is an image he cultivates, he dresses the part and is well known for his penchant for the dramatic, with his mutton-chop sideburns and Sherlock Holmes pipe. If ever I do anything wrong and find myself up before a judge, he is the person I’d want as my lawyer.
In Scotland, you have to stand in the witness box, and I always slip off my shoes so that I feel grounded. Nobody can see I have done that. You are aware that the jury is watching you and so you adopt your best poker face. The defence QC was called to cross-examine me but remained seated, allowing an expectant hush to descend on the room. Then, in a move worthy of a television legal drama, he leaned down under his desk and lifted out a big, heavy textbook. Rising slowly to his feet, to emphasize its weight, he slammed it on the bench in front of him with a theatrical flourish and a blast of dust. It was the most recent edition of Gray’s Anatomy, the anatomist’s bible. His opening words, enunciated in his cultured Edinburgh accent, are burned into my memory: “Now, Professor, I am not doubting you for a moment . . .”
And so began an intense grilling in which I was questioned on how the bone develops in the child, how it grows, how it fractures, the soft tissue surrounding the bone and the process of differential exclusion that led me to my conclusion as to the specific anatomical position of the fragment and that it was from the left side of the skull and not the right. The prosecutor, by asking me questions that I was not qualified to answer, had cut off many of the other avenues that I am sure the defence QC would have liked to explore, such as whether the fragment could have belonged to someone else, how it might have got into the washing machine, and so on. Such are the dark arts of the legal process to which the expert witness must remain alert.
I was finished by lunchtime and on the train home thirty minutes later. I felt my credibility as an expert in the eyes of the jury had survived the cross-examination relatively intact; that I’d been able to convey my evidence in a manner they would understand, and to give them a realistic impression of the weight of my belief in the identification of the bone fragment without being overly dogmatic. And that was the end of my involvement.
After that, like everyone else, I had to watch the news and read the newspapers to find out what happened. It is a peculiar feeling to be so intimately involved in some parts of a process and yet to be excluded from so much of it. As scientists, we don’t have a personal investment in any case—that would be unprofessional, not to mention detrimental to our own mental health—but you do experience something of a sense of closure when you read the outcome of a trial in the papers.
In this case, Mary’s husband was found guilty of culpable homicide (roughly equivalent to manslaughter in English law) rather than murder, and sentenced to six years in prison. He was given an additional six-year sentence for perverting the course of justice by concealing the whereabouts of her body. He appealed and his sentence was reduced to nine years. In practice he served only half of that time, much of it in an open prison. I heard recently that shortly after his release he had moved down to the Blackpool area and remarried. A woman’s capacity for trust and forgiveness never ceases to amaze.
Sometime after the appeal, I met the defence QC at a training workshop and good-naturedly berated him for giving me such a hard time in the witness box when my evidence was not particularly critical to the outcome of the case. The police had been able to identify that the bone fragment belonged to Mary through DNA and her husband had largely confessed to her death and the disposal of her body. We had to go to court because he stopped short of admitting to murder or culpable homicide. But of course, I appreciate that the best of defence lawyers will fight every point for their client, always drilling down into every single piece of evidence in search of a weakness in the evidence itself or in the expert’s credentials, understanding or processes.
The QC’s response to me, in his dry, Scottish drawl, was: “Aye. But you are so much more fun to question than the pathologists. They are much easier to trip up.” And people wonder why I hate going to court.
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Because the skull is three-dimensional, almost egg-like in shape, and comprised of so many different elements, each of which may have a slightly different structure, it is not surprising that there is a real art to the identification of injuries to it. When they are particularly complex, and especially when we have to try to fit together pieces of a shattered skull, it takes quite a lot of experience to work out what is what, what has happened and how.
I had been working as a forensic anthropologist at Dundee University for six years or so when I was asked by the police to review the mystifying death of a ninety-two-year-old man. The nature of the fractures to his skull, and indeed the whole question of the manner of his death, remained largely unexplained. As a new cold case team trawled through the evidence, some four years after the event, in search of a different thread to follow, they thought that perhaps anthropology could bring something fresh to their discussions.
At the police station the pathologist and I sat down with the cold case team and went over the details of the case to try to establish whether there was anything that might have been missed in the first investigation or which merited further follow-up. Much of the evidence was not challenged—until we came to the manner of death. The pathologist told us all he was prepared to say was that death had been due to multiple traumas to the head. He could not explain, though, how only one little spot of blood was found in the room where the man had died, or how he came to be lying face down on the floor with a piece of the frontal lobe of his brain on the carpet in front of him. The analysis of the brain had indicated that there was no tracking, which means that nothing had entered the skull, and yet somehow this piece of brain tissue had become detached and been expelled through a wound over his left eye.
Around the table all sorts of unlikely theories were thrown down, dissected, analysed and rejected. As the day wore on, they became more and more fantastical and we had to call a halt to our brainstorming session. It was clear that what we needed to do was to take all the crime-scene and postmortem photographs and X-rays of the body away with us, sit down somewhere quiet to examine them all in detail and think,
think and think some more to see if we could develop a theoretical possibility that might explain the death and the wounds in the context of the crime-scene evidence. The body itself was no longer available to us because it had been cremated shortly after the man died. This is why comprehensive, clear and accurate photography is essential to every investigation: you have no way of knowing what evidence may be required in the future.
Colin had served in the Royal Navy in the Second World War. He had never married and had lived alone in his well-kept bungalow for forty years. He was well known and well liked, but kept himself to himself. He was very active and had been an excellent ice-skater, swimmer, walker and even water-skier until quite late in life. His neighbours reported that he went out early every morning to the local newsagent for his papers and had been seen doing so on his last day, a fact confirmed by the newsagent.
But later on, noticing that his milk had not been collected from the front doorstep, some of his neighbours went over to make sure all was well. When he didn’t answer the doorbell they walked around his bungalow, looking in through the windows and calling out to him. Peering into the window to the spare bedroom at the back of the house, they saw him lying face down on the floor. The ambulance and the police were called but it was too late. Colin was dead. Initially, nobody suspected foul play. It was thought he had probably had a heart attack and had died where he had fallen. Only when the emergency services turned over his body did it become clear that an entirely different set of circumstances had led to his death and that it involved a second person.
As there was no forced entry to the bungalow it was possible that Colin knew his attacker. He had quite a bit of money saved up, which he kept at home, but that was untouched. Nothing else seemed to be missing, either, so burglary was ruled out as a motive.
