Just look at a sunbeam streaming through the window and you will notice that it is full of little specks, floating and swirling with any little disturbance. Most of us are unaware of this so-called air spora* we breathe in. After all, one of the prime purposes of the mucous membranes lining our noses is to trap little bits of foreign material and prevent them from penetrating too deeply into our sinuses and our lungs. But those of us with sensitivities or allergies certainly suffer the effects of these irritants. For considerable periods they can remain trapped on the membranes in our nasal cavities, especially on those covering the turbinate bones, the groove-like air passages that divide our nasal airways, and direct inhaled air to flow steadily into our lungs. We have no idea how long these particles can remain intact, and experiments to find out would be virtually impossible. The opportunities to observe the actual pollen load of the turbinates are necessarily rare; there are, after all, only so many corpses to be stripped down and examined. Yet, thanks in particular to some of my cases, the screening of cadavers for the palynomorphs, inside as well as outside them, have gradually become acceptable to pathologists at post-mortem examination. Crimes have been exposed, and justice has been served, by virtue of the things our bodies have accidentally acquired.
Go back in time 25 years, to the city of Magdeburg, sitting high upon the River Elbe in Saxony-Anhalt, Germany. Magdeburg has experienced the wild ups and downs of history more than most other settlements of its size and, in 1994, another piece of its grisly past was exposed. The foundations for a new apartment block were being excavated in the middle of the city when a mass grave, containing 32 unidentified skeletons, was unearthed. Based on witness reports, and the poor state of the dentition of the victims, they were thought to be Soviet soldiers; but the Magdeburg community was divided in its opinion on who was responsible for the deaths. There was every chance that, in the tumultuous spring of 1945, the Gestapo had carried out the mass killing, but the rival theory was that the agents of the Soviet intelligence agency, SMERSH, which had had its post-war headquarters in Magdeburg, probably murdered them while putting down a revolt in 1953. If the Gestapo had done it, it must have happened in the spring whereas the revolt put down by SMERSH happened in the summer. Reinhard Szibor from the Otto von Guericke University in Magdeburg thought that if the season could be established, the riddle would be solved.
The turbinates are high up in the nasal passages and are formed from a veritable coral reef of very thin bone, covered by thin mucous membranes. The stickiness of the membranes means that any particle becomes trapped on them until the mucus is removed by nose-blowing. Szibor decided to check whether he could differentiate between spring and summer pollen trapped in the turbinates of the buried victims, and a year-long experiment seemed to prove the validity of his theory. He asked one of his graduate students to blow his nose at regular intervals across a year, and to then identify the pollen grains in the series of handkerchiefs. The results led them to believe that they could, indeed, differentiate spring from summer pollen from the handkerchiefs. He considered that alder, hazel, willow, and juniper would represent spring, while rye, plantain, and lime would be more abundant in the summer. Based on his observations, and this one set of nasal observations, he came to the conclusion that the victims had met their end in the summer and consequently that, rather than the Gestapo, SMERSH had been responsible for these particular killings.
Pollen had been used to date archaeological discoveries before – but Szibor’s was the first to attempt its retrieval from the turbinate bones of skulls. He was convinced that he had demonstrated a difference between spring and summer by this method, and I was very impressed by this. But the BBC showed me a video of him demonstrating his technique and, although I had been invited to the studio to extol the virtue of the method on the popular programme Tomorrow’s World, the viewing in the green room before the programme made me decidedly uneasy. After the viewing, I was more than sceptical of the perfect results that Szibor had claimed. Szibor was not a botanist and seemed to have ignored both contamination and the phenomenon of pollen residuality. If one season’s pollen had been preserved in the Magdeburg soil for well over 40 years, it was likely that pollen from all the seasons was there too. I have worked long and hard in soil palynology and, in some soils, preservation can be very good indeed – but the soil matrix is likely to contain the input for a whole year, and even pollen from previous years. Certainly soil animals, especially earthworms, and many tiny arthropods, mix huge amounts throughout the profile so that various seasons’ pollen would be likely to be mixed up. I thus had to question how Szibor found one season’s pollen on the turbinate bones that had been buried in soil for 40 years, and likely to have been grossly contaminated by it. He claimed excellent differentiation, but it is possible that his findings were fortuitous.
Nevertheless, in spite of my reservations, I thought this was a brilliant idea. In my view, it is utterly essential to eliminate contamination of the turbinate from any part of the skull, and the soil comparator samples would need to be thoroughly homogenised so that a true picture of its pollen load could be gained. From then on, whenever I had the opportunity, I flushed out cadavers’ turbinates to see if it would give useful evidence. It certainly proved so in a few investigations and, in 2000, six years after my first tentative steps into the forensic arena, the technique helped to solve the riddle of a young man strangled in a Hampshire woodland.
On a bitter December day, two mornings after Christmas in the year 2000, a man was out with his dog, working off the effects of too many mince pies and enjoying the brisk winter air in an area of woodland about 12 miles north-west of Portsmouth. Nowadays it is mostly modern plantation but it still retains some vestiges of the ancient Royal Forest of Bere and, criss-crossed as it is by bridleways and paths, it is some of the most accessible woodland in Hampshire. The man’s dog suddenly scooted off and disappeared into the trees, and he did not respond to his master’s whistling, which was very unusual for him. A little further on at the edge of the path, the dense undergrowth gave way to a sloping area of turf, obviously kept short by rabbits and deer, and perennially wet, as evidenced by clumps of rushes and sedges poking through here and there. It was an obvious place to get into the trees without having to do combat with brambles and dead bracken.
The man stopped and listened. He could hear frustrated whimpering to his left – and that was where he found his dog in a little glade, and he was scraping at a round object poking out of the soil beneath a huge beech tree. The man pulled his dog away and poked at the object with his walking stick but lurched back in fear when he saw that the round object had an ear. The head was face down and the rest of the body was buried.
A large log had been placed over the grave. It is strange, but murderers often mark a grave in some way, possibly to make it easier to find. Many have been known to revisit the graves of victims, possibly to check whether the body is sufficiently hidden. But who really knows what goes on in their minds?
Soon, police officers arrived to set up the inner and outer cordons and some unfortunate constables were allocated to guard duty. The victim had been missing from his home in Portsmouth for more than six weeks by the time the police called a forensic archaeologist to retrieve the body. His family had got through this Christmas, not knowing where their 24-year-old son had gone and, after he was reported missing, no one was able to give them any answers. All that anyone knew was that he was last seen in his white Ford Escort van at Hilsea Lido in Portsmouth on 11th November. That same van, on the very same night, had been found on a local industrial estate, set ablaze and destroyed.
The dead man was definitely in a state of decay, but the low winter temperatures must have slowed the process so much that no standard decomposition model would have been able to establish how long he had lain there. The pathologist quickly established how he had been killed and, although there was a deep knife wound in his side, what had finished him off was tight garrotting. A cord had been put around hi
s throat and, using a stick at the back of the neck, the cord had been wound, round and round, until he was throttled. It was a brutal killing. It later came to light that he was murdered because he had taunted one of his ‘mates’, obviously a man with a vicious temper and dominant enough to implicate an accomplice. The police also established that the victim had not exactly been the most law-abiding of citizens. A joiner by trade, detectives believed that he had carried out a number of burglaries on an exclusive housing development close to where he lived. By thorough, routine police work, two suspects were identified; one of them had been seen in the victim’s van on the night he vanished. As a matter of routine protocol, footwear from both suspects, and a vehicle belonging to one of them, were seized as exhibits to support a prosecution case against them.
And that is where I came into the case.
Woodland has been a favoured place to dispose of bodies since time immemorial, and there are woodlands in Britain that might even be regarded as mass graves. I was once involved in a case for the Metropolitan Police where they were searching a woodland for 24 victims of a gangland boss, the burials having occurred over a number of years. In the Hampshire case, the sinister place holding the victim’s grave would under normal circumstances have been a most delightful glade. There were several large beeches, but also holly, hazel, and wild cherry. There were banks of bramble at the edges and the gnarled, twisting stems of old honeysuckle plants were winding and grasping at the stout supports offered by shrubs and trees. Much of the ground was covered by glossy ivy, which had managed to creep up some tree trunks in its quest for light. This was winter and the ground was rather bare except for thick layers of beech leaves, beech nuts, and acorns, and, although there were many trees bordering the glade, a bridle path could be seen through the gaps in the winter branches.
The question the Senior Investigating Officer (SIO) wanted answered was whether the victim had been killed in the wood or if there were, in fact, two crime scenes. Had he been transported to his grave or had he been living when he came to this glade and killed right here where we stood? We also had to ascertain whether the shoes belonging to the suspects had contacted the scene. As fortune would have it the police had quickly identified two suspects, and they gave me their footwear, along with the floor mats and foot pedals of the main suspect’s car. Indeed, one can only claim ‘shoes’ and not point to a person because of the habit that criminals have of sharing footwear; because of this I needed to be able to eliminate as many other places as possible as being sources of the profile that I had retrieved from the suspects’ belongings. One good thing about this case was that both parties were very much ‘city’ boys and very unlikely candidates for taking walks in the woods for pleasure. That, of course, would not prevent any defence barrister claiming that they did just that, so I had to be prepared.
The whole area, including the public car park about a third of a mile away, had been closed to walkers and visitors. I walked from the car to the grave with John Ford, the tough police sergeant who was responsible for the day-to-day running of the case, and I was pleasantly surprised to discover that he was genuinely interested in what I was doing and wanted to learn about vegetation and plants. He had a broad Hampshire accent which made him seem homely, but I soon learned how tough he could be. He was determined to gather every scrap of evidence that might offer itself. I liked him. He was open and blunt, and I knew I could work with him.
As we walked along the path created by estate workers for the benefit of public access and enjoyment, I marvelled at the richness of the landscape around us. This was a huge area of woodland – a patchwork of woodlands within woodlands, each with its own character and species profile. There were obvious plantations of conifers and dense stands of birch, but there were also magnificent old beeches and oaks, with an understory of hazel, holly, and a tangle of the bare stems of many species defying immediate identification in this winter light. There were many stands of sweet chestnut trees that in antiquity provided essential food in southern Europe and were brought to Britain by the Romans. There were also individual trees of one of our four native conifers – the dark, brooding yew. One patchwork piece of woodland merged into the next, but the herbs, which would open up into another kaleidoscope of colours in the spring, could only be predicted at this point because they were in their winter slumber with little showing above ground.
As I walked along, I was envisaging the kinds of botanical profile each area might yield. But one thing I have learned, and novices still cannot grasp, is that one can never be sure what will be revealed. I could make broad predictions – I knew that there would be high levels of pine and birch pollen near the car park, that sweet chestnut would hardly register because it produces relatively little pollen, and that there would be more oak than beech, even though beech trees were numerous. But the exact quantities and patterning? Analysis would be needed to reveal this and no modelling exercise would give results that could ever stand scrutiny in court. Every case is unique and must be treated as such.
After all my training and experience in archaeology and ancient landscape reconstruction, one thing that originally and still continues to surprise me is that every sample I collected from the surface soil would be different from the next and, the further I sampled away from the first, the greater the difference would become. In fact, everywhere, pollen fallout is patchy and only moderately predictable. Its patterning can be seen in terms of spectra, one spectrum merging into another as the vegetation changes. As I have mentioned a number of times, when comparing objects and places, it is essential to collect sufficient comparator samples to enable the ‘picture of place’ to be constructed. It also helps enormously if some rare speck of trace evidence makes that place particularly distinctive. Nothing must be left to chance if one is to give a robust performance in court – for performance it certainly is. Half-baked predictions in the absence of hard evidence would soon be torn to shreds if the barrister on the opposite side were worth his salt. I was also aware that I had to be strict with myself so that I would not be infected by the innocent enthusiasm of police officers for the desired outcome – conviction. I am always conscious that one must constantly fight cognitive bias.
No palynological analysis can ever offer absolute proof of contact. Everything must be viewed in terms of likelihood and, every time I make a recommendation or report to the police, I am careful to add the appropriate caveats. One must look for alternative scenarios that might account for any profile obtained from a suspect; and this essentially was to lead my police companion and me a merry dance across Hampshire and West Sussex.
No one could have reached the grave site by car, and the victim would have had to be walked, or carried, to his death. This meant that I needed to identify the easiest way in and out of the site from the road, and to target my samples in any place likely to have been contacted by the offenders. The main and obvious one, of course, was the grave itself; that is one place they could not avoid. I was given the footwear, floor mats, and foot pedals of the main suspect’s car for analysis, and my word, there were close comparisons with the samples from the crime scene itself; and importantly there were some remarkable specific markers. All the trees and shrubs I had seen were very well represented and, in the spring, the place must have been exquisite. The pollen and spores showed that the site had lots of bluebells, wood anemones, dog’s mercury, ferns, and other herbs that are characteristic of such places, but most remarkable was something I had never, ever found before – Solomon’s seal. My microscope also picked out some peculiar fungal spores that looked like the legs on the Isle of Man flag, without the ‘knees’ being bent. These turned out to be the spores of Triposporium elegans, a microfungus that infects beech nuts particularly. Not only all that, but I also registered a hay meadow assemblage right in the middle of this quite dense woodland. That might have presented a bit of a conundrum if it had not been for my experience in that Yorkshire cellar, and the fact that I had noted a bridle path near the grave sit
e. It was obvious to me that the hay meadow profile had come from the horse dung. This gave the crime scene a high degree of specificity – a signal of hay meadow within deep woodland.
The pathways in and out of the grave site were important, but so was anywhere else frequented by the suspects. This led to lengthy visits with John, my police sergeant companion, to the suspects’ homes and all their favourite haunts. The experiences proved to be arduous but not without humour, especially when visiting various addresses in Portsmouth itself. We needed to check out the palynological status of a number of modest terraced houses in some less favoured parts of the city, and the contrast of one with another was astonishing. I clearly remember the first one. Walking through the dark narrow hall, avoiding the huge jumble of coats on hooks just inside the front door, really sticks in my mind. It opened out into a living room that could only be described as chilly and sparse. There was no hint of homeliness, although the baby crawling on the threadbare carpet looked bonny and clean. The room led through a scullery, then on to an entirely neglected backyard, and an excuse for a garden. There were old buckets, neglected toys, and old boots in the backyard, and some of the weeds, including docks and nettles, growing between the paving stones were about 30cm tall. A dejected clothing line with abandoned pegs hung slackly along from the house to a scruffy shed, and the whole dwelling left me feeling sad.
Not so the next one. It was a two-up, two-down terraced house like the other one, but that was where the similarity ended. This one had new double-glazed windows and had been extended out towards the garden. A woman opened the door in a cloud of a strong, woody perfume and immediately one could tell she had money. She was expertly made up, with hair too blonde to be blonde, and smoking a cigarette. She was wearing black leather trousers, a black sweater, and several bright gold chains, neck to waist. Pink toenails peeped from her glittery mules and her long fingernails had been manicured into fashionable squares with white-painted tips. Several rings adorned her hands, one of which was a large diamond cluster. The décor was a revelation – lush red carpet, black leather sofa and chair with fur cushions, and an elaborate crystal chandelier slung from the ceiling. The TV was as huge as a cinema screen and the little bar that had been squeezed into a corner was groaning with bottles of booze and glasses. The modernised fitted kitchen led outside into a sterile space of immaculately clean concrete slabs, with one or two tubs of dead flowers from last summer. There was nothing at either of these houses that resembled the vegetation where the body had been found. I had not expected there to be and could tell at a glance that there was no need of comparator samples and analysis from these places.
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