Translator: Reka Rozsa Reviewer: Mirjana Čutura
Wim Develter: I'd like to start with a story.
On a sunny Friday afternoon in June 2008,
Peter Van Heel, a 58-year-old farmer, was walking on his fields
when suddenly, he discovered a body.
He was totally in panic and called the police.
And as we are Belgium's largest forensic department,
we were appointed for the crime scene investigation.
So, arriving on the crime scene,
I could see the remnants of a decomposing adult.
And all the clothes were burned.
But there were no signs of fire accelerants.
And when we took a closer look,
I could see some fancy jewels on the hands,
so I thought, 'This must be a woman.'
And there were some ropes visible around her wrists and feet.
And as I turned the head a little bit,
I could see three round skin perforations in the neck.
So that's where we knew
this victim, probably a woman, was shot, murdered,
packed, transported, dumped and burned.
So, the obvious questions everybody asked themselves are,
'What happened?'
'Who is this person?'
and, 'When did it happen?'
To answer these, we transported the victim to the mortuary,
where we did a total-body CT scan, a forensic autopsy
and a forensic anthropological examination -
so, the study of the bones.
So, during routine autopsy,
we tried to use these rods,
and we put them through the holes of the bullets
in order to reconstruct the bullets' trajectory.
And it's kind of difficult and time-consuming.
And even in a fresh body, it's already very difficult.
So, in this case, with decomposition,
this task becomes nearly impossible.
But when you take a look at the damage
caused by a bullet when it goes through a head,
it perforates the skin, the skull,
and on its path, you have some scattering of bony fragments from the skull,
little fragments, metallic fragments from the bullet, air and blood.
So we were thinking,
'Can't we use our CT data
to reconstruct in a digital way a bullet trajectory?'
So, I did what every Belgian guy does with a problem:
I went to the pub.
And together with the forensic engineers and forensic radiologists,
we got drunk,
drunk of ideas, of course.
And the day after,
we had a huge scientific hangover
as we were realising the complexity of our idea
because we had to test and validate our idea on a model,
on an animal model, of course.
So we chose sheep.
Not because they're ugly or stupid,
but because they have a large brain volume,
and they're easy to get.
So, after two years of programming and testing,
we succeeded to visualise the damage.
But now, we had to apply this to human skulls and human heads.
So, this is how it works.
Our engineers created a matrix
in which all the heads are divided
in thousands and thousands of little cubes.
And each little cube of the traumatised head -
so, meaning the head that has been shot -
is compared with the same cube in the same anatomical position
of the normal head,
repeating that process for all the cubes in the traumatised head
to all the heads in a normal data set.
So, that was a huge effort of time,
and after a while, we succeeded.
And what came out was fantastic,
as you can see in this video.
We succeeded
to create the bullet trajectories.
So, in this victim,
the victim was shot with three gunshots in the neck.
And only one was directly lethal,
and that's the red one dissecting the right vertebral artery.
So, this approach has many advantages.
First of all, it's fast.
It's much faster than an autopsy.
It's not invasive, so your pathologists just don't have to cut anymore.
And it's more accurate.
Like in a ricochet -
that means when a bullet changes direction in the head -
that can easily be seen with our software tool.
But that's simply not possible with these rods.
And last but not least,
even in decomposition like in this case,
if you know the bullet's trajectory,
you will know through which anatomical structures it will go.
So, this question is answered.
We know how this victim died.
Still two questions to go:
who is it and when did it happen?
So, being burned and decomposing,
visual identification is not possible.
And having no dental treatment,
forensic odontology is not an option either.
So the only thing remaining is forensic anthropology.
So, what do those bones tell us?
So, based on the description and measurements
of the forms and the bones of the skeleton,
we are able to see something about stature.
In this case, this victim was about 172 to 177.
Also about the gender -
well, it appeared that there was an 80 percent probability
that this person was a man.
So, not a woman with fancy jewels.
And he was probably Caucasian.
And the age - and that's a tough one -
between 23 and 57.
So, that's rough science, isn't it?
We could need some help there.
So that's why we sent out a Mayday
to our friends and colleagues forensic geneticists.
Bram Bekaert: Right. So, we have an age range of about 34 years.
That's huge, isn't it?
I bet this description fits about half the men
present here in this theatre.
So, if you want to be able to put a name down to this body,
we need to narrow this group down.
And this is where forensic genetics might help a bit.
Now, the standard procedure for the identification of a person
is to produce a DNA profile using a blood sample, for example,
or a muscle tissue
and generate a profile
and compare that to a toothbrush or a profile from his mum or dad
if you have some idea who that person is,
and get a formal identification in this way.
But what if you have absolutely no idea who this victim is?
Well, there's lots of information in our DNA sequence
that can actually reveal what we look like.
You know, we can use someone's DNA just in the same way
as an eyewitness would give a description of someone.
We can almost generate a DNA photofit.
Now, what can DNA tell us today?
Well, we can tell someone's eye, hair and skin colour, for example,
with fairly good accuracy.
But we can also tell where someone is originally from
through a biogeographical ancestry test.
And my colleague Peter Claes told you last year on this same forum
about this new revolutionary technique of 3D facial morphology
just by looking at someone's DNA.
Now, this is all helpful and wonderful, obviously,
but age is a very important factor too
when you're trying to build an image of someone.
And the classical methods that provide age ranges today,
such as anthropology, odontology,
are just not good enough.
So, this is where our second idea came from.
We wanted to develop a new age-estimation test
basically with far better accuracy.
And we wanted to do so from a single drop of blood.
So, how did we do this?
Well, there are several processes in our body
that make sure that we don't like ageing, right,
that we make room for the next generation.
Some of these processes are, for example,
that our heart size increases, our heart rate decreases,
our bones tend to shrink in size, and our muscles weaken.
But what's causing these changes, you know, during the ageing process
has been the subject for many, many years now.
And it's only recently come to light
that DNA methylation plays a major role during the ageing process.
Now, DNA methylation is a chemical process
where small caps are being put on our DNA in order to activate or inactivate genes,
thereby changing the characteristics of the cell.
It's a natural process that occurs in our body.
Now, why DNA methylation changes during ageing, we're not sure yet,
but what we do know is that our environment -
and by that I mean what we drink, what we eat, whether we smoke,
whether we have much stress to endure, for example -
has an effect on these DNA methylation patterns.
So, when we get older,
the more of these environmental effects affect our DNA methylation patterns,
they change,
and that's something we can measure.
Now, in order to develop a test to estimate age,
we looked at the DNA methylation patterns in four regions of our DNA
in over 200 individuals with a known age.
So, with that data, we were able to develop a model
that we can now use to predict the age of people.
If you can tell from this graph,
we've got the predicted ages plotted against the actual ages.
You can tell that they're very, very similar.
So, we can use this data now, basically this model,
to estimate the age of people with an unknown age
and this with an accuracy of less than four years.
That's a five-fold difference compared to the more traditional techniques,
such as anthropology and odontology.
We're basically calculating someone's biological age or epigenetic age
to determine his actual or chronological age.
Now, what can we do with this test, which we've initially called DNAge?
But I've just recently found out a couple of days ago
that DNAge is actually a very well-known anti-ageing, moisturising cream,
so forget the name.
(Laughter)
We can estimate the age of deceased individuals
just as in our burned case that Wim presented.
But we can also estimate the age of living individuals,
people who claim to be older or younger than their official documents tell you.
Very importantly for forensics,
we can also estimate the age of bloodstains of people
who left bloodstains at crime scenes,
you know, to help identify the offender.
And intriguingly, you can also use this test
to prove that a bloodstain was, for example, left seven years earlier,
prior to when the crime was committed
and prove the suspect innocent of a crime he's accused of.
Now, because these DNA methylation patterns
are very, very stable,
you can also use them in cold cases -
cases that have been left on the shelf
for several years, perhaps 30 years, for example,
and can be solved right now.
So, back to our case.
We confirmed through regular DNA profile he's male.
We know through our biogeographical ancestry test
that he's most probably from Southeast Asian descent.
And we now know that he's about 36 years old,
give or take two and a half years.
That's a lot more information
that the police can now use to identify the suspect.
So we have one more issue left:
time of death.
Now, the time of death
has always been sort of the Holy Grail in forensic medicine
because it provides useful information
to verify alibis from suspects, from witnesses,
but also the timelines of the victim itself:
you know, where was the victim prior to his death, who was he with?
So the more accurate your time of death estimation is,
the better these timelines will be.
Now, everybody who's ever seen, you know,
CSI series, or series such as 'Silent Witness' -
and to be honest, I love that show -
you know these three standard parameters that forensic pathologists use:
pooling of red blood cells towards the lower parts of the body,
muscle stiffening
and cooling down of the body temperature.
Now, what's most of the times left out in the series
is that this method has very large error range.
Estimating the time of death is very challenging
because it's dependent on a large number of external variables,
such as the type and the number of layers of clothing
that a person was wearing,
the temperature of where the location was where the victim was lying
or whether that person had a fever due to an overdose of drugs.
Now, in this case, in our burned-victim case,
Wim estimated the time of death at about two to three days ago.
And that's pretty vague.
And many, many researchers
have already tried to improve the time of death estimation.
But we've come up with a completely novel method
which is complementary to the methods used by the forensic pathologists.
And we're using information from our own biological clock.
Now, our biological clock
is a 24-hour pattern of behavioural, physiological and biological aspects
which is evolutionary conserved.
It's the annoying thing that wakes you up
those five precious minutes right before your alarm clock goes off.
Why?
Or the annoying thing, you know,
why your wife falls asleep right next to you
after you just started that fantastic movie with Mel Gibson.
Anyway, so the biological clock
plays a large number of important physiological roles.
And two of well-known hormones, called cortisol or melatonin,
they fluctuate in this 24-hour pattern, and they're part of this biological clock,
and they peek at different times of the day.
Melatonin, for example - it's the sleep inducing hormone -
it peeks during the night,
while cortisol - it's the stress hormone - it peeks early morning.
Now, when a person dies,
all the biological processes in his body stop.
And so does the biological clock.
So, when we take a blood sample from that person,
it provides us with a unique snapshot of exactly the time that person died.
So, when we measure the concentrations of cortisol and melatonin,
we can indeed have already an idea of when a person died:
whether early morning, midday, evening or night.
But we wanted to improve on that.
We wanted to improve the accuracy of this test
to within two hours of the actual time of death.
And we're looking at identifying more of these rhythmic markers,
such as RNA markers, which are the products of your DNA,
or metabolites, which are the products of our metabolism.
And we're calling it 'our forensic molecular clock'.
Now, with our three ideas,
we're now able to determine the exact cause of death.
We've got a lot more information to identify our victim,
and we now know the exact time of death.
But we're only beginning to get a grasp of the ideas, of the information
that's still available in bloodstains or other biomolecules
that are still available on crime scenes, for example,
but it's very difficult to predict what future of forensics will be.
What we do know, however, is that we're not at the end of our means,
but only at the beginning of what nobody could've imagined before.
We're basically turning fiction into reality.
Thank you.
(Applause)