I had never done investigative work like this before but the idea intrigued me, writes DR MARK A. SPENCER
The phone rang on my desk at the Natural History Museum in London, where I was curator of the national herbarium — a unique and vast collection of British plants. It was the police. They had a potential murder on their hands.
The rotting remains of an unidentified man had been found covered in vegetation beside a river, but no one knew how long he had been there. Could I, with my specialist botanical knowledge, possibly help?
I had never done investigative work like this before but the idea intrigued me — even after I had seen detailed photographs of the badly decomposed body, the rib cage, spine and partially de-fleshed skull exposed, the teeth bared.
I agreed, though I did wonder whether an academic like me had the stomach for such gruesome field work.
But the die was cast and not long afterwards I found myself in a small town on the edge of the Pennines, down on my hands and knees, poring over a patch of waste ground behind a warehouse.
The body had been removed to the mortuary but decaying human tissue and the gut-wrenching stink of death remained. I retched but managed to carry on with my forensic inspection of the heavily overgrown site.
Japanese knotweed and buddleia abounded, but the vegetation flattened by the body was what I knew to be Himalayan balsam, a species that dies back every winter and regrows in the spring.
I examined the crushed stems closely and calculated that the plant in question was six months old and that from the amount of regrowth that had taken place, it was likely the body had been lying there for two months — vital information the police needed to resolve the case.
My job was done. But on the way back to London on the train, I felt on edge — and it wasn’t just the cloying smell of decay that clung to me, however much I tried to wash it off. I also felt excited by what I’d just done and fascinated by its possibilities. I had been looking at and studying plants for 40 years, ever since I was a kid, and lurking in my brain was a lot of information. Suddenly, I realised my expertise could have a practical use in helping to solve crimes.
Back in the museum, I couldn’t wait for the phone to ring again with another request for my help. And so a new and unusual career opened up for me — as a forensic botanist, uncovering evidence for criminal cases from plant life.
For the past dozen years I have been ‘that flower bloke’, as some hard-bitten detectives have characterised me when I turn up at a crime scene.
But even the most dismissive soon come to appreciate the important insights my obscure knowledge brings to tricky murder cases and the search for missing bodies.
A trained scientific eye can unearth vital clues. Disturbed or unusual foliage may point to where a corpse is buried.
A speck of pollen on a suspect’s clothing can prove his or her presence at a crime scene. A leaf remnant stuck in the mud on the shoe of a killer or rapist may be crucial.
I examined the crushed stems closely and calculated that the plant in question was six months old and that from the amount of regrowth that had taken place, it was likely the body had been lying there for two months — vital information the police needed to resolve the case (stock image)
A crushed flower stalk may hide a secret that solves a case.
So criminals beware! That rose bush you brushed past so casually, that bluebell you unknowingly stepped on, that spore lodged in a trouser turn-up, may be enough for the ‘flower bloke’ to track you down and bring you to justice.
You see, once a dead person is placed in a natural environment, plants and animals respond to and accommodate it.
Take the bramble. To most people they are a nuisance, a straggling tripwire guaranteed to snag you while you’re tramping through the countryside.
But I am always happy to see them at a crime scene, because they are of particular assistance to the forensic botanist.
They tend to be common in places where people are in evidence because the presence of humans — through agriculture, sewage and transport — increases the nutrient load of soil and watercourses.
Brambles are greedy feeders and the extra nutrients we supply are to their liking, so they thrive in these conditions and that makes them useful as what you might call vegetable calendars.
A bramble thicket may look like a chaotic mess but in fact it is an elegant and choreographed structure.
By carefully examining the position of the stems under and around a body and observing how they have aged, I can estimate with some certainty how long the body has been lying there.
Japanese knotweed and buddleia abounded, but the vegetation flattened by the body was what I knew to be Himalayan balsam (stock image pictured), a species that dies back every winter and regrows in the spring
It is not pleasant work. But for me, being in the presence of the dead is an intense experience. When I am called to a crime scene where a body has been discovered, their remains are often a testament to what befell them and I know that in a way I am witnessing the last moments of a person’s life.
I feel very connected to them and care about them, their family and friends.
Unlike most people, I find no particular horror in decaying flesh and skeletal remains.
The true horror is in the minds of the perpetrators of the crime under investigation. They are the ones who must try to sleep at night and are bound to re-live what they have done.
Only once, while on forensic duties have I felt a flutter of emotional disturbance, when a victim bore a striking resemblance to a member of my family.
I see decomposition as an amazing biological process and the remains of the dead as extraordinarily beautiful and complex. Corpses are the hub of new life as maggots, insects and other organisms take over.
My fieldwork is generally done in ditches and other dank environments, scrabbling around in the dirt with secateurs to remove roots and stems that have grown through and over human remains.
But that’s OK because there’s nothing I like more than a patch of marsh to go squelching around in.
In many of the cases I have been asked to investigate, I have almost nothing to go on. Yet even the smallest bit of plant life can yield clues. Once, the police sent me two tiny pieces of leaf that had been recovered from the victim of a violent sexual assault.
The victim was unable to recall where the attack had happened, so the police were hoping these battered, greenish-brown fragments could show the precise location. I carried them around my laboratory with great care.
It was going to be a daunting task to identify them from the 5,000 species of wild plant that grow in the UK. But after ploughing through a chunky volume entitled New Flora Of The British Isles, I narrowed down the leaf fragments to a tree or shrub.
Birch was my instinctive guess. But I needed proper confirmation, and that meant rummaging through the collection of five million dried plant specimens in the Natural History Museum’s herbarium.
Bingo! Examination under a microscope showed the leaf fragments were a match for the silver birch.Next stop for me was the area where the assault was believed to have taken place, a bleak, isolated spot on the outskirts of a small town in southern England.
The most abundant trees and shrubs were hawthorn, oak and ash but I found two small areas of silver birch and was able to give detectives my opinion that this had been the scene of the crime.
Peak season for me is usually October to March, when many trees are bare and bodies come to light more easily.
It is often dog walkers who report finding human remains. Our sense of smell is vastly inferior to that of dogs. When trees and shrubs are in full leaf and a dog bounds into the bushes, the owner is far less likely to see what has aroused their hound’s excitement.
So criminals beware! That rose bush you brushed past so casually, that bluebell you unknowingly stepped on, that spore lodged in a trouser turn-up, may be enough for the ‘flower bloke’ to track you down and bring you to justice (stock image)
But as the leaves fall, the dead are revealed.
It was a dog walker who found one body I remember well.
It was midwinter and bitterly cold when I was called to a railway embankment where the heavily decayed remains of a man had been found.
Rain had fallen for several days and the ground was wet and slippery. The embankment was steep and I kept sliding back as I hauled myself up to where the body lay. He was wearing all-weather gear and lying on his back.
His body appeared to be in quite a relaxed position, legs stretched out, arms by his sides.
The vegetation around him showed no signs of significant damage, which ruled out a struggle, and I could not see an obvious exit route created by another person through the nettles, brambles, buddleia and Japanese knotweed.
His upper torso, head and arms were resting on the vegetation flattened by the weight of his body. His lower torso and legs had slid underneath the sprawling stems of a bramble bush.
It was as if he had climbed into bed and pulled up the blanket halfway.
Overall, the vegetation evidence suggested he had simply stopped walking, lain down and died. It seemed almost peaceful.
As the body was carried away, I set myself the task of finding the route to his final resting place, which overlooked a housing estate, roads and a football pitch.
I moved very carefully, not wanting to slip and disturb anything. The damage to plant stems and branches was erratic.
He appeared to have lurched up and down the bank for about 30 metres until he came to a stop and died.
As I examined the Japanese knotweed at the scene, I could see that the damaged portions included smaller side branches supporting the remains of fluffy white flowers.
These flowers open in late summer, so I was able to estimate that the man’s remains had been there for several months.
A few days later, I learnt that he had been identified. He had been physically and mentally unwell for several years, sleeping rough, and had not been seen by family members for at least a year.
My role model in such work is Dr Arthur Koehler, a pioneer in forensic biology. Back in 1932 in America, his brilliance provided vital evidence to convict the man who had kidnapped and murdered the infant son of the aviator Charles Lindbergh.
A makeshift wooden ladder had been used to reach the boy’s bedroom and abduct him.
Dr Koehler, who worked for the U.S. Forest Service, identified the wood it was made from as North Carolina pine. Using microscopy, he established that the machine tooling on the surface was made by blades rotating at 2,700 revolutions per minute.
After inquiries at more than 1,500 sawmills, one was identified as the source of the wood.
It was a mill where the chief suspect, Bruno Hauptmann, was known to have worked.
The vegetation around him showed no signs of significant damage, which ruled out a struggle, and I could not see an obvious exit route created by another person through the nettles, brambles, buddleia and Japanese knotweed (stock image pictured)
Dr Koehler was then able to prove that a carpenter’s plane owned by the suspect had been used to make the ladder.
Afterwards, he wrote in praise of ‘the reliability of the testimony of trees. They show with absolute fidelity the progress of the years, storms, droughts, floods, injuries and any human touch. A tree never lies. You cannot fake or make a tree.’
This advice was valuable when detectives were convinced a certain gangster had been killed when a punishment beating went too far and buried in woodland.
They suspected the body was in an ivy-covered clearing behind dense laurel and holly.
But my careful search of the area showed the trees and bushes had been undisturbed for at least two years.
This knowledge enabled the police to refocus their investigation. They established that the body had been put in an oil drum, sealed with concrete and dropped in a lake.
Investigating dead bodies and discovering their secrets is not glamorous. Don’t be fooled by the way television tends to portray crime scene forensics.
The likes of Silent Witness’s Nikki Alexander (played by Emilia Fox) wow us with their expertise in everything from entomology (the study of insects) to criminal psychology, fingerprinting, DNA analysis and gunshot residue.
Most individuals are not that gifted. I work alongside other forensic scientists who specialise in different aspects of the environment — soil, insects, arvae, fungi and so on — and pool my knowledge with theirs. It is the only way.
Those TV dramas get so many of the basics wrong.
Often, the lead investigator, not wearing the all-important protective suit, saunters under the perimeter barrier and into the tent around the remains of a murder victim, then stoops to retrieve a crucial piece of evidence on the end of a pen.
If that happened in real life, the police officer managing the crime scene would go ballistic — and rightly so.
It’s wrong, too, to suggest that high-tech gadgets can solve crimes in the blink of an eye. In reality, in my case, solving crimes mostly comes down to careful observation, patience, a good microscope and an equally good pair of wellies.
- Adapted from Murder Most Florid: Inside The Mind Of A Forensic Botanist, by Dr Mark A. Spencer, published by Quadrille at £16.99 © Dr Mark A. Spencer 2019. To order a copy for £13.60 (offer valid to December 11, 2019; p&p free), call 01603 648155.