When Professor Lorna Dawson was growing up, the plants, crops and soil on and around her father’s Angus farm was a recurring source of interest.

Why did certain plants love one kind of soil and not another?  What is the ground under our feet made up of?

What were the factors that made soil in one place so different from that found somewhere else?  

Seasons changed, the soil grew hard with frost or softened with rain; plants rotted, shoots appeared.

“You could say that soil is embedded within me,” she says, remembering travelling with her mum around the county, testing each other to spot and name the plants they passed on the way.

“It fascinated me why different things grew in different places.”

Prof. Lorna Dawson, head of soil forensics at the James Hutton InstituteProf. Lorna Dawson, head of soil forensics at the James Hutton Institute She didn’t realise then how soil could hold so many dark secrets...

That there would come a time when the tiniest smudge might be the ‘smoking gun’ that jailed rapists and killers or secure the freedom of the innocent.

Or that it might lead her on a journey to the very depths of human depravity and at the same time bring comfort to the grieving.

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As Head of Soil Forensics Group at The James Hutton Institute, untangling the secrets of soil has taken her to some of the UK most infamous crime scenes and the highest courts in the land.

In her hands, it’s provided vital evidence that helped crack decades of mystery surrounding the infamous World’s End murders. Trace evidence found on the soles of victim Helen Scott's feet matched the soil in the field where she was buried – shattering killer Angus Sinclair’s alibi.

More recently, Prof. Dawson’s evidence helped convict serial sex offender Iain Packer for the killing of Emma Caldwell: soil found at two locations close to where her body was found in April 2005, were revealed to be a 97% match with samples taken from his van.

 

Emma Caldwell was murdered by Iain Packer in 2005Emma Caldwell was murdered by Iain Packer in 2005

It was the missing link in a case that had defied justice and drifted for years, much to the distress of the 27-year-old Ms Caldwell’s grieving family.

Confronted in the High Court with the damning evidence, Packer’s defence crumbled. 

Her expertise aided detectives as they unravelled what happened to charity cyclist Tony Parsons. His body was recovered on the remote Auch Estate at Bridge of Orchy in January 2021.

And early next year when excavations begin at the site of Tuam Mother and Baby Home in County Galway, where an estimated 800 babies are believed to have died, they will focus on the area where analysis of the soil’s fatty acids and volatile organic compounds indicated the likelihood of bodies.

There have been dozens of other deeply disturbing cases, some recent, others cold cases at home and further afield.

Becky Godden's killer Christopher Halliwell's conviction was aided by soil analysisBecky Godden's killer Christopher Halliwell's conviction was aided by soil analysis In Swindon, soil deposits on a fork and pick axe in the home of taxi driver Christopher Halliwell led to his conviction for the rape and murder of Becky Godden more than a decade earlier.

It was crucial: detectives had failed to gather important evidence earlier in the case leaving them scrambling to piece together the evidence needed for a conviction.

There was also the disturbing murder of Hina Bashir, killed by a man “obsessed” by her, who stuffed her body in a suitcase and dumped it in undergrowth.

Soil on Muhammad Arslan’s shoes linked him to the site and helped seal his guilt.

Soil on his shoes helped to convict Hina Bashir's killerSoil on his shoes helped to convict Hina Bashir's killer Among the successful results are some which continue to perplex: Prof. Dawson and her team have aided teams seeking to solve the mysteries of what happened to Ben Needham, the little boy who went missing on holiday in Greece and, closer to home, Moira Anderson.

At the pioneering laboratory, one of the few in the world devoted to forensic soil science, the smallest smudge of mud can point the way to bodies, smash alibis and uncover suspects’ trails.

To come as technology develops, they could even time travel, using the DNA of the miniscule living elements of soil – bacteria, fungi, algae and nemotoids - to piece together not just what may have happened, but, crucially, when.

“We’d need to work with biomatics people who understand big data, and microbial scientists so we can understand why certain organisms change, to help answer questions like ‘when did that person visit that site?’,” she explains.

“If we have the microbial data that tells us - if we understand it fully - about whether someone has been there in spring, summer, autumn or winter.

“That changes possibly on a week’s basis, because the bacteria respond to very subtle shifts in temperature moisture and predation.

“That’s really exciting,” she adds. “We’re not yet using that but ten years from now, that will be a very powerful tool.”

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Meanwhile, Prof Dawson and the expertise of the James Hutton Institute, home to Scotland’s National Soil Archive which holds more than 60,000 soil samples dating back to 1934, are in demand around the globe.

It began with a simple request for help from the soil specialist at least 20 years ago.

“A Grampian police officer brought a spade and said ‘Can you find out where that soil might have come from came from?’ and I said ‘okay, I’ll give it a go’,” she recalls.  

Analysis suggested it probably came from a particular woodland. Sniffer dogs were sent out, drugs were found and before long she was pioneering a new branch of forensic science.

Soil analysis in criminal cases was not necessarily new: Arthur Conan Doyle touched on it A Study in Scarlet, when Sherlock Holmes was praised by sidekick Watson for his knack of instantly identifying muddy splashes on trouser fabric with the part of London the wearer had just walked through.

Prof. Lorna Dawson has worked of many of Scotland's most notorious criminal casesProf. Lorna Dawson has worked of many of Scotland's most notorious criminal cases In the real world, modern science, remarkable foresight and Scotland’s immense soil archive – a  90-year-old ‘time capsule’ which gives insight into past soil conditions and offers scientists instant access to a huge variety of soils – laid the foundation for what would become a world-leading facility in demand internationally for its expertise.

Key was vital funding that laid down the necessary lab protocols, staff training, peer review and accreditation that showed soil forensics would withstand courtroom scrutiny.

“You don’t want to use junk science when it’s something as important as someone’s liberty,” says Prof. Dawson.

Moira Anderson disappeared in Coatbridge on 23 February 1957Moira Anderson disappeared in Coatbridge on 23 February 1957

As soil forensics grew, other countries took note: she has been engaged by legal teams as far away as Australia to help bring criminal investigations to a head.

One case was that of Australian barrister Lloyd Rayney, accused of murdering his wife and burying her in a park.

With part of the case hinging on soil inside seed pods found in the victim’s hair said to match samples from the couple’s home, the defendant’s legal team wanted to question the prosecution case.

“We reviewed the work that had been done there and found there were severe limitations, with no consideration of alternative propositions of where the soil might have come from,” she says.

“They said soil had come from the backyard of where she lived, but when we looked further up the street there were more similarities with the material.

“They hadn’t considered that wider context, and he was found not guilty.”

Another involved a series of young women all killed in similar circumstances in the Claremont area of Perth, Western Australia.

“We were able to identify material on one of the victims that helped link to the suspect in that case, who has now been convicted of the girls’ murders,” she adds.

Prof. Lorna Dawson has reported and advised on more than 150 casesProf. Lorna Dawson has reported and advised on more than 150 cases (Image: Derek Ironside) Dr Dawson is a member of the International Union of Geological Scientists Initiative on Forensic Geology, working with police forces and scientists in their own country to train them in UK-established techniques, covering how to collect evidential samples, process, analyse and present the evidence in court.

It’s led to her sharing knowledge with teams in Portugal, Brazil and the FBI in America.

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While each case is different, whether working as part of a police probe or for an accused’s defence, the approach has to be the same – neutral and objective.

The nature of some, though, can take their toll.

“We tend to anonymous the samples; when they come to laboratory they are given a unique lab code so we are not affected by any potential bias.

“You try to be objective and impartial and not think about individuals.

“But that doesn’t mean to say you are not always very aware of the sensitive context upon which we all work, and that once you present it in court and it’s gone through the legal process you don’t sometimes think ‘gosh that was extremely sad’.

“But to do your work, you have to stay objective.”

Still, she adds: “There was one case... I was examining the clothing of a child victim. It was the same pyjamas that my little one had, and that got to me.

“Then, the Karen Buckley case,” she continues.

Dirt found on Alexander Pacteau’s car tyres showed he had been at the same Glasgow park where his victim, Irish nurse Karen Buckley’s body was found.

It was crucial evidence leading to his conviction.

Nurse Karen Buckley's killer was trapped after soil linked him to the spot where she was foundNurse Karen Buckley's killer was trapped after soil linked him to the spot where she was found (Image: Police) “We worked on that case and my daughter had just gone to university at the same time,” she adds.

“I was probably an over-sensitive mother at that time, and I was aware that these very sad things can happen to innocent people.”

She has reported and advised on more than 150 cases, written over 100 expert witness reports in the UK and overseas and given evidence in more than 20 cases.

Not surprisingly, her depth of knowledge has been tapped by leading crime writers and recognised with a string of awards. Among them, a CBE and the most recent, the Honorary Fellowship of the Royal Scottish Geographical Society Honorary Fellowship, presented after a series of lectures for the organisation.

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She says she already had her “dream job” when, more than two decades ago, that police officer handed her a mucky spade and suggested it might help in a criminal investigation.

“To apply that to the criminal justice system, it felt really worthwhile, and something that mattered,” she says.

"I feel very honoured and privileged to be invited to help people, whether that’s the police force helping to search for missing people or whether it’s helping a lawyer to build a case where they feel there has been an injustice.”