The Importance of Soil in Forensic Science
Transcriber: Andrew Piccioni
Reviewer: Amanda Zhu
You could say that soil is in my blood
coming from a long line
of farmers and growers,
agriculturalists,
people who looked after the land.
But one day,
my blood was literally in the soil.
Let me take you back to the 1970s,
in the countryside of Angus,
where we had tattie holidays.
You remember?
Tattie holidays where we picked potatoes.
We were out in the outdoors
with our friends,
exercising in the fresh air,
having fun and having breaks.
But one year, I took it a bit too far.
I climbed on top of the bogey,
the trailer,
and someone came behind me
and pushed me,
and I fell.
I fell into the ground
and fractured my leg in two places,
an open fracture.
The blood sipping down,
I drifted in and out of consciousness.
I saw the sky above me
and the clouds drifting past.
Eventually, I was rescued.
After a period of recovery,
I was allowed to go home.
And while I was at home,
I couldn’t climb the trees
and run around the countryside
like I liked to do.
That was no longer the case.
So I turned to books.
I liked Agatha Christie,
but I also loved
Sir Arthur Conan Doyle’s books.
Remember the Sherlock Holmes books?
‘[Hound] of the Baskervilles’,
‘Sign of the Four’.
Many of his stories included soil science.
He was fantastic about science.
He engaged his readers.
He used the medical knowledge that he had.
He was also an avid botanist,
and in ‘The Sign of the Four’,
he described the red mud
that was on a visitor’s shoes,
which identified which part of London
that the visitor had been -
Wigmore Street in London -
to the particular place where he had been.
Little did I know that 20 years later,
I’d be using those same principles
of transfer of soil
to someone or an object
that can tell us where they have been.
The next phase of my life
was when I went to university
from the idyllic countryside of Angus
to the big city of Edinburgh.
When I got there,
I moved into halls of residence,
enjoying sailing, running,
going up Arthur’s Seat,
having a wonderful time
and also learning too.
But while I was there,
I went back to my halls of residence room,
which overlooks Salisbury Crags
and Arthur’s Seat,
and on the news came the announcement:
Two young girls
had been found in the fields
outside Edinburgh,
one at Gosford Bay
and one in the fields
at Huntington/Coates.
They’d been gagged and bound and left,
left with no dignity.
No one was found for these murders
for a long, long time.
It was the world’s end
for those girls that day,
Christine Eadie and Helen Scott,
and their families and friends.
Life would never, ever be the same
for them ever again.
And these investigations
got the iconic term:
the World’s End Murders.
Unfortunately, no one was found.
And we are students,
young girls living
and studying in Edinburgh.
Our lives changed.
No longer would we go home alone
to our flats or halls of residence,
but we go together
or we get the bus or a taxi.
No more home late
from the library at night
going through the meadows.
That all stopped.
Our lives have changed,
but not as much as the lives
of the families and friends
of poor Helen and Christine.
But I carried on with my studies
in soil science,
and I came up to Aberdeen,
the lovely city that it is.
And part of the privilege
of being a researcher
is that you get to meet other people.
You get to go to conferences
and attend various meetings.
And in April 1999,
I was in London at a meeting.
And at that time,
I also like watching programmes
such as Crimewatch.
And I thought Jill Dando
was an amazing woman.
She was to me the Lady Diana
of presenting.
And one day, just as she was
about to get married,
she was going home to her own house
in the streets of London,
and she was shot dead.
(Gunshot)
Her life was taken.
Her world ended
and that of her family and friends
at that point in time.
So, an investigation
went underway very rapidly
with multiple lines of inquiry.
But very soon, a suspect, Barry George,
was identified.
Barry George lived
nearby where Jill Dando lived.
And very quickly, evidence was produced,
evidence of a particle of gunshot residue
that was found in his pocket.
Using a very high power microscope,
they identified that that particle
was exactly the same type
as the particle that they recovered
from Jill Dando’s hair.
That was quite a crucial
piece of evidence
that was presented and used in his trial.
In 2001, he was found guilty
and sent to prison.
However, we have to consider
alternative propositions
in forensic science.
Where else could that single particle
of gunshot residue have come from?
This is London.
There are undergrounds.
There are armed police.
So a report was sent to the courts,
which said,
‘Considering the single particle
of gunshot residue
that was found in Barry George’s pocket,
it was just as likely that he did not kill
Jill Dando as kill her.
So in 2008 and in an appeal court,
he was acquitted and released from prison.
To this day, they have still not found
who killed Jill Dando.
We consider the alternative proposition,
as I’ve said,
but let’s think about it.
Let’s think about if I see you
and you have just been to a wedding,
you’ve confetti in your hair
and your shoulders and your clothes.
It’s safe to assume
that you’ve likely just been to a wedding.
However, if I meet you
and you’ve got a single piece
of confetti in your pocket,
it’s more likely that you have picked up
that piece of confetti
by going to a pub and meeting someone
that has been to a wedding.
So we don’t always take
things at face value.
We consider the evidence
and the evidence in context.
So, moving forward to 1984 -
And I can’t do a talk without mentioning
DNA and Sir Alec Jeffreys,
who discovered
the individual nature of DNA
and how DNA is individual
to a single person -
apart from identical twins, that is.
But each one of you will leave behind
particles in your seat,
which would let us know
where you have sat here today,
you have been here,
and you will have less choices.
So that tells us who has been there.
And what happened at this time was
a database was built up,
a searchable database.
The combination of computing science,
biology and chemistry,
all came together.
And at that time,
a Mr Angus Sinclair was in prison,
in Peterhead prison -
a lifetime sentence
for the abduction and rape
of 11 young girls.
And as it happens,
their DNA is put into the database,
and his DNA was an actual match
for the DNA that was found
at both Christine Eadie
and Helen Scott’s sites
where they were found.
That wasn’t enough, however.
It wasn’t enough because he said
that it was consensual sex.
So we have to consider
what other evidence can be developed.
Crime light was a new method
that was developed at that time -
and I’ll come back to this
later in the talk.
But what it does
is it shines a light on where the DNA is
on the person or object.
So it combines the ‘who’ with ‘where’
to let the investigators
work out what happened.
So let me go back to my life now.
And in 2000, I was working away
at the then Macaulay Institute
in Aberdeen,
and along came Police Scotland -
or at that time,
that was Grampian Police -
and said, ’We’ve got this spade.
There’s some soil on it.
Can you help us and work out
where it might have been used?
We’ve got some intelligence of some drugs
buried in a woodland near here.′
So I took the soil,
and myself and my colleagues,
we ran it through a whole load of tests,
we compared it with a database
that we had of soils,
and we quickly narrowed it down
to a specific woodland,
with specific types of trees
on a Countesswells series soil.
Went there, and the drugs haul
was indeed buried in that woodland.
My passion for forensic soil science
was firmly established at that time.
Then in 2003,
It was Lothian and Borders Police
that got in touch,
and they said,
’We’ve got soil samples that were kept
from 1977 in the World’s End Murders.
Would you be able
to have a look at them
and tell us if they can help us identify
where the people had been?′
Of course,
we could apply those same principles
that I read about many years before,
that to develop a discipline
that was strategic,
it was quantitative, it was robust.
So we did that, we looked at it,
and we could show that indeed, Helen -
the soil on her feet -
was from that field where she was found.
But that wasn’t enough.
What we did was
we developed other techniques,
organic biomarkers,
which could identify
at the scale of a footprint
where someone had stood.
And that led us to build up a picture
that indeed, poor Helen had walked,
she had walked from the edge of the field
where the caravanette
that she’d been abducted into.
She’d walked over the grass verge
and into the field to her death.
The combination of identifying individual
aggregates of soil from her feet
and the methodology
that had developed to the point
that we could apply those biomarkers
to those individual samples -
several samples,
multiple samples, not just one -
so the prosecutors, the investigators
came to the conclusion
that Angus Sinclair had indeed taken
those girls and killed them
and indeed, Helen Scott
had walked to her death.
The biology, the DNA had told them,
with the crime light and the DNA,
that he had tied the knots
in the ligature in their neck.
The soil had showed that she’d been alive
and walked to her death,
and the semen on the coat
had put a time on that:
when he blamed his brother in law
and he said he’d gone fishing.
But in 2014,
he was found guilty,
and he was sentenced to 37 years.
A year for every year
that the families of these girls
had to wait to see justice brought.
Ironically, in that year, later,
more developments came to fruition,
and we could then show that the past,
the bloodstain the size
of a 50-pence piece
was necessary to get DNA,
but now, the rim of a glass
is enough to have enough DNA
that tells that it was you
that drank out of that glass.
In the past, we would have to have
a handful of soil;
now we can analyse soil the
size of a grain of rice.
And in 2019,
Crimewatch presented a whole feature
on the World’s End Murders,
and that very day, Angus Sinclair died.
So we can say who did something
by the DNA on the object.
We can say where someone has come from
by the soil on their shoes.
But that doesn’t tell us
about how it got there.
If your neighbour shakes your hand,
and your neighbour goes
and kills someone with a knife,
your DNA is on that knife.
If your friend borrows your car,
and they go and bury someone
in a grave in a wood,
the soil from that grave site
is in your car.
So it’s the how that is so important.
The data must be reproducible,
fair and robust and tested.
You may think what is it to do with me?
I’m not a scientist; I’m not a lawyer;
I’m not a police person.
You’re a public citizen.
What if -
What if …
you were the victim of a crime?
What if …
your family, someone you knew
were falsely accused
of committing a crime?
You would want the truth to be heard.
You would demand that justice be served.
But you would want it to be fair,
to unreproducible.
So who knows what’s going
to happen in the future?
Who knows what the next exciting
scientific development is going to be?
Could be soil DNA.
It could be environmental DNA.
Who knows?
We have to keep the curiosity
of the young children
to discover the new discoveries
that will help solve the cold cases
and the cases yet to come.
And we’ve got to fund them,
we’ve got to fund them appropriately
that the data is robust
to produce future sound science
so that just decisions can be made,
so that we can all help
with sound science
to provide the evidence
to help and to be the people
that help the silent victims of crime.
(Applause)