The Perfect Murder Crime Scenes Scotland: Forensics Squad

DNA samples and nail scrapings were also taken.

This was a chilling murder in a quiet part of Scotland.

Probably never seen that type of crime before.

NEWS REPORTER: It was at this point on Arbroath Seagate Beach

that the grim discovery was made this morning.

When we got there, we knew it was no joke.

These men thought they had committed the perfect murder.

It was a real surprise when we found out

there was this woman living in a shed.

We found a dead body underneath the floorboards of the living room.

We were never able to establish the cause of death.

I believe in Scotland we've been able to deliver a unique service.

To identify suspects is one thing,

and then to prove people are guilty of a crime

is something completely different.

Although you see a lot of dead people,

you treat everyone as an individual and with respect and with humanity.

Forensic scientists - they are silent witnesses

and they are the eyes and ears of law enforcement.

This time, the forensic team reveal the perfect murders.

So carefully planned, the killers thought they'd escape justice.

On the 1st of April 2008,

Graham McMillan had just been promoted to Chief Inspector

and Head of CID for Angus,

one of the most widespread rural regions in the United Kingdom.

Once I had completed unpacking,

I had a look on our Command Control system,

which logs all the incidents

that the police within Tayside are dealing with at that time.

There was one jumped out at me,

which was "head found on beach in Arbroath."

Two young children while walking along the beach

had come across a black plastic bin liner.

In that bin liner, the children had seen the dismembered head

of a human being.

I'm sure it was a very gruesome discovery for those young kids.

The children were understandably shocked by such a gruesome find.

Officers trained in counselling were quickly brought in to help them cope

and take their statements without further trauma.

They were aged about eight and 11 at the time.

Quite a horrific find for them.

Dr Victoria Morton is head of Scene Examination,

responsible for overseeing every murder site in Scotland.

Outdoor murders are extra challenging.

It was such a windy day that it was very difficult

to actually put up any type of tenting.

There was actually a police officer standing with tarpaulin

to try and shield the scene examination staff, the biologists

and the police activity

so that the press didn't get any gruesome pictures.

We were very, very keen to engage early on

with the Senior Investigating Officer to make sure

that we would be securing the evidence

before either the wind, the rain or the tide had an impact on it.

There'd been quite a storm the night before

and there was a lot of items washed up on the shore.

A few hundred yards down from where the head was lying

we found a pair of hands.

Body parts were found over there beside those white buildings.

Where did they come from?

Well, local fishermen have been mulling that over.

They say pretty much anywhere.

Perhaps from the south, from Dundee or Edinburgh,

perhaps down from the north, and Aberdeen.

One thing they are sure about,

this is the first time in living memory

a body has been found in Arbroath beach.

The dismembered hands which were found in a separate bag

to the head on the beach had been cut in a specific way.

The person or persons involved

maybe had some connection with the butchery or meat industry.

Essential that we identified who this person was,

because at this time all we had was some body parts.

We didn't know what the circumstances were,

who this person was.

This kind of murder was a rarity.

And the head had deteriorated by being in the sea for a long time.

So Graham decided he needed highly specialist advice.

The Centre for Anatomy and Human Identification at Dundee University

could help by creating a postmortem depiction of the head.

Now, a postmortem depiction is a type of forensic art

that gives a professional judgment

on what this person would have looked like in life.

While waiting for the facial reconstruction of the victim,

the mark enhancement technicians at the Dundee labs

examine the bags for any evidence.

Crucially, they recovered a few hairs.

DNA samples and nail scrapings were also taken.

but they struggled to develop any fingerprints

that might have been left on the bags.

Day two focused on the postmortem,

where the three individual body parts, the head and the two hands,

were treated almost as if they were from different individuals.

You couldn't assume at that point that they were from one person.

As we were looking closely at the teeth,

they recognised that some of the dental work

probably wasn't up to the standard that they would have expected

in the UK.

When the reconstructed head came back from Dundee University,

it was photographed to go to the media.

She's believed to have been white.

Aged in her mid-20s to mid-30s.

She has brown eyes, brown eyebrows and shoulder-length brown hair.

She had a pale complexion

with light freckling across the nose and cheekbones.

There is a distinctive scar, circular shaped scar,

in the middle of her forehead just below her hairline.

Now that we have a description of the woman,

what's the procedure in trying to identify her?

This is an area where you do have a high degree, high number

of migrant workers, usually from Eastern Europe.

So, it could well be that in the coming days and weeks,

this investigation spreads far beyond these shores.

But Graham got a swift and unexpected break.

The victim was immediately recognised

by one of his own officers.

The girl in the picture was a young female migrant worker,

Jolante Bledaite.

We sent officers up to her home, which was a flat in Brechin,

to just check the place out.

When they entered the flat,

they could see that her room was absolutely emptied.

There was nothing. Not an item in it.

They also spotted a bloodstain on a door frame.

On seeing that, they immediately withdrew

and we called up for forensic assistance.

Really fortunate that they had actually found

this small area of bloodstaining.

We took a sample from that area

and that later did turn out to be a sample which yielded some DNA.

The blood on the door frame matched. It was Jolante Bledaite.

The police investigation quickly gathered speed.

Graham McMillan began interviewing potential witnesses,

like work colleagues and residents of the block.

Graham's professional intuition focused on two men.

One of them was her flatmate

and the other one was a friend, but had worked in the past with her.

Something just didn't square up with these guys.

Both suspects, like Jolante, were migrant workers.

Vitas Plytnykas was 41 years old,

and Aleksandras Skirda was 20.

A thorough examination of the flat in Brechin

where Jolante Bledaite had lived was conducted.

This was a very thorough search.

In the bathroom, dilute bloodstains were found.

Blood mixed with water.

We also examined carpet.

Although the room didn't show too much blood on the outer surface,

as we lifted the carpet up there was a significant amount of blood

on the underside of the carpet.

Was this the site where the body was maybe cut up?

Was this the site where someone had been killed and then moved on?

And we then began to look in the flat in a more detailed way,

trying to understand what horrific event

had actually happened in this flat.

There was blood found within the bath and some blood spatters,

and the pattern of those were very useful

in finding out whether she was alive or dead when she was decapitated.

The inside of the flat was revealing its grisly secrets,

but there was more to come outside.

There was a small cellar area in this block of flats

and in there was a wheelie bin.

When scene examiners looked inside this wheelie bin,

they found some bags of clothing and personal belongings.

Her clothing had bloodstaining

and, again, through forensic examination and analysis

back in the laboratory, we were able to identify

that it actually came from the deceased.

There was some gaffer tape found there

which had lots of long human head hairs on them,

which looked to have been forcibly removed.

As it was wrapped around the head

and then pulled off subsequently, it would pull hair out from her head

and we were able to obtain DNA profile

from the roots of that head hair.

In addition to the hair,

there were faint bloodstains on the gaffer tape.

Again, DNA profiles matched Jolante Bledaite.

But there were further revelations and a breakthrough

when mark enhancement specialists examined the tape.

We recovered some DNA and some fingerprints

and the DNA and the fingerprints

matched back to one of the suspects in this particular case.

During Skirda's interrogation, he was impassive,

but soon cracks began to show in his story.

He'd known Jolante for... a good two years.

They had lived together within the flat

and they'd also co-habited in previous accommodation.

At first, he didn't really show any emotion during the interviews.

It clearly was affecting him, and he was wanting to get it off his chest.

Skirda started talking

and very quickly implicated the older suspect.

Plytnykas' background hinted at a violent past.

He said Vitas Plytnykas very much led the crime

and the planning of it.

He'd served in the military in the past in Afghanistan

in the Russian army, we believe, and he was quite a violent man

who I think a lot of the community were in fear of.

We had good evidence to put her murder at that location

in Brechin, and we also had evidence linking Skirda to the deceased.

Skirda had blurted out a stark confession.

Graham McMillan and his team had to focus on corroborating it.

Forensic teams were redirected to many deposition sites.

It was a huge area that it covered.

Stuff dumped in bins, in rivers, in parks, right throughout Angus.

Scene examiners were called out to study burnt items

found by a river bank.

These proved to be vital.

We received a phone call from the police to ask us

to send a team of scene examiners down to the river,

and on close examination of the burnt area

the team recognised documents, personal documents,

that were written in a foreign language, not in English.

In further and closer examination

it turned out it was actually the burnt remains of a passport.

That passport did indeed belong to the deceased.

I had teams working on gathering CCTV

to corroborate that the movements that he said they made.

More incriminating footage emerged from CCTV on a bus.

The suspects carried the head and hands in bin bags

for disposal in Arbroath.

That left Jolante's torso.

They arranged for someone to give them a lift down to Arbroath

with a large suitcase,

using the excuse that one of the accused was moving to a new flat.

Once they had been dropped off,

CCTV revealed even more shocking evidence.

The two men wheeled Jolante's torso inside a suitcase on a trolley

in broad daylight through Arbroath town centre.

Quite nonchalantly strolling down to the harbour

and then returning empty-handed.

MORTON: The police investigation

also led to another examination on day five.

One of our scene examination teams

were dispatched to a garage to look at a car of interest.

This car was actually owned by a friend of one of the suspects.

They initially noticed that the car was extremely clean,

both on the inside and outside of the car, almost to the point

where it looked as if it had been valeted in some way.

The crime scene examiners found it unusual that no fingerprints

or fibres whatsoever were present inside or on a car.

I called upon the services

of the Grampian police underwater search team.

These guys came down that day and started their searches for us.

They conducted searches of the harbour

in the most difficult situation and environment that you can imagine.

The water was freezing cold.

The currents are extremely strong just by the harbour wall.

It's quite a silt-based sea bed there, so visibility was next to nil,

so, you know, the stamina that they had,

the cold and the currents were sapping their strength,

and to cap it all they were conducting a fingertip search

of the sea bed looking for Jolante.

They recovered the case.

Once we had that and secured it,

we again called upon forensic teams and scene managers

to manage the actual removal of the case and Jolante's body

from the sea up onto the harbour wall.

Whenever we opened the suitcase,

the suitcase was covered in a lot of silt

because it had obviously been in the water for some time now.

There were a large number of stones in the suitcase.

Obviously someone had the intention of making sure

that that suitcase did not come up to the surface again.

And also in the suitcase we found a torso

with the arms and the legs in situ, of a human being.

We didn't know that the hands and the head and the body

were all from the same individual, so we obtained DNA profiles

from all of those components and they obviously had the same profile.

We also checked the vaginal swabs

to see if there was any evidence of semen.

That was a long shot, but we did it nonetheless.

Also looked at tapings or swabs taken of the body

to see if we could find any foreign DNA

from people that may have dragged the body around.

The handle had been ripped from the case,

and forensic scientists worked on it.

It was a success.

It matched the handle found at the house with holes in the suitcase.

Then, another breakthrough.

The material used to bind Jolante's feet

matched material from the murder site.

On day six, the Grampian Police dive team were deployed

to recover any potential evidence from the River Esk near Brechin.

The underwater search team also assisted us

in the recovery of knives that we believe were used

in removing her head and hands from her body.

There were three knives found in the river Esk,

which runs near to the flat that Jolante lived in.

There was a lot of forensic evidence against Skirda.

There was clothing,

which we found DNA that indicated he was the wearer of that clothing

and also blood that matched that of the deceased.

After Skirda blamed Plytnykas,

his flat became the focus of intensive forensic examination.

But nothing incriminating was discovered.

The absence of forensic evidence does not mean someone has not

been involved in a crime.

The absence of evidence could suggest that the individual

who hasn't left material at the crime scene

maybe took precautions to ensure that material was not left.

With no hard evidence, the investigation ground to a halt.

It was DI Gary Ogilvie's job to interview Plytnykas.

I interviewed Vitas Plytnykas on four occasions

during the course of his time spent within police custody.

I found him to be a very, very cold, very callous,

very strange individual.

He certainly wouldn't commit to anything.

The first three interviews had been fairly bland

in that he basically refused to contribute to anything

that I had put to him.

The interviews went nowhere.

But Gary continued to probe Plytnykas for weaknesses.

He got his breakthrough

with conversations on the suspect's Russian Army experiences -

particularly the wounds he had sustained as a serving soldier.

He opened up and began to speak to me and began to interact with me

and he seemed to be a completely different person

in that he was relaxed and willing to commit to certain things.

Plytnykas suggested that during his service in the army

that he had conducted similar decapitations

during the occupation of Afghanistan.

And likewise he also had, as part of living in rural Lithuania,

some basic butchery skills.

But nothing about Plytnykas's army career

or witnessing decapitations was used in court.

What actually happened at Jolante's flat that night finally emerged,

and it was a gruesome story.

After years of hard work, Jolante had saved ?12,000.

It was a lot of money to her.

And the conspirators.

They knew about her savings,

her plans to buy her own home in Lithuania

and that she would leave soon.

When Jolante said she was renting a spare room

to another migrant worker,

the men realised they had to act before the lodger arrived.

Callously, they pounced on the helpless woman while she slept.

They'd bound her and were threatening her with violence

so they could extract her PIN number from her.

They were using the knife

and there were some puncture wounds on her body

which we discovered during the postmortem

and later were matched with the knives recovered from the river.

Once she gave them the PIN number, it was Plytnykas who went

to test if he could withdraw money from the account,

leaving Skirda standing guard over Jolante during that period.

I can only imagine what was going through her mind

while she was waiting for his return,

knowing that she'd given him the wrong number.

On his return, it would appear that further violence

was evinced against her to make her give the true PIN number.

Once the true number was given by Jolante,

Plytnykas left the flat to check at the bank

to see if he could successfully withdraw money,

which he was able to do on that occasion.

And that sealed Jolante's fate.

They brutally murdered her,

then disposed of her body and belongings

to make it look like she had returned to Lithuania.

Jolante was smothered in her bed, taken into the bath,

where she was decapitated and her hands removed.

They cleared the flat as best they could,

hid her body in a small cellar.

Over the next couple of days,

they disposed of various items of her property.

Her ID cards were burnt.

The weapons that they'd used during the crime

were disposed of in a river and other clothing, cosmetics...

all her personal belongings

were basically scattered to the four winds over Angus.

I think these men thought they had committed the perfect murder.

They thought that, you know, as long as they disposed of her body

and all her belongings in a thorough manner

then they would have all the time in the world to withdraw the money

from her account at their own leisure and never, ever be found for it.

The killers knew her head and hands would identify her,

so dumped them in different places.

Then they chose the aptly named Danger Point

to throw her torso in the sea.

Plytnykas and Skirda must have thought they'd got away with it.

But they hadn't planned on a huge storm or the North Sea tides.

The head and hands washed up on the beach.

Two men are due to appear in court today

in connection with the death of a Lithuanian woman

whose severed head and hands were found on a beach in Arbroath.

These are the two men found guilty

of the horrific murder of Jolante Bledaite.

Vitas Plytnykas and Aleksandras Skirda

dismembered and disposed of her body.

Sentencing the men, the Judge Lord Pentland said...

We made contact with the authorities in Europe

to establish if they had previous convictions.

It's a routine matter that we would do.

Skirda wasn't known to the police, however, Plytnykas was.

Plytnykas had been previously convicted of manslaughter

by a German court.

Coincidentally, his conviction for murdering Jolante Bledaite

came within months of another high profile case

involving a foreign national, featured in a previous episode.

Slovakian Marek Harcar

was jailed for killing Moira Jones -

a Glasgow businesswoman.

Both murders provoked outrage in the media

and calls were made for tighter border controls

for foreign nationals with criminal records.

One of the leading campaigners was Moira's mother, Beatrice Jones.

I don't believe there's anyone in this country

who would say, "Yes, let violent criminals in."

It's as simple as that.

I can't think of anyone, whatever political persuasion,

who'd say, "But we're for this,

"we want these people to be allowed to come in."

Come on.

We've got enough baddies of our own.

It's as simple as that.

In the future, new, improved profiling equipment

will access overseas databases

to identify international criminals faster.

Carol Weston, the Senior Forensic Scientist on the Moira Jones case,

is studying this now.

Another development that will be rolled out very soon

is the kits that we use to create DNA profiles.

At the moment, we look at ten different areas

that vary between individuals.

The new kits, however, will look at 17 areas,

or in some cases 24 areas, that differ between individuals.

This gives us the power to search databases across the world

as opposed to just our own databases

because they'll all be more compatible with each other.

But, more importantly, it means that our DNA technology

will be much more sensitive.

So we'll be able to get DNA profiles from very small stains

or very old stains -

things that our kits are not quite sensitive enough for at the moment -

and this could be fantastic,

especially in cold cases where we might need to go back

and look at some very small and very old samples.

Rapid advances in forensics technology

make murder even harder to get away with.

Yet some people still believe they can commit the perfect crime.

Occasionally a case comes up

where the truth is truly more bizarre than fiction.

A woman had been reported missing by her children

and they were concerned

about the information they were given at the time by the father.

The missing mother was 47-year-old Carol Jarvis.

When police knocked the door at the family home in Bathgate,

her husband Harry answered.

He told the officers his wife was there and called her.

A woman crawled out from under the bed.

But it wasn't his wife.

The identity of the woman was later revealed

as former millionairess 57-year-old Rita Heyster.

Police were immediately suspicious

and got a warrant to search the house.

He had since left the house,

we believe, with this other woman, Carol.

She hadn't been found. We didn't know where she was.

And that obviously led to a search of the house.

And they discovered a dead body

underneath the floorboards of the living room.

At that point, the police are keen to ascertain

exactly who that person is.

One, is it a female?

Is it the missing person, Carol Jarvis?

And be able to recover that body as quickly as possible

to be able to confirm that.

The immediate task was to recover any forensic material

without compromising other evidence at the scene.

This also meant sifting through piles of junk.

It was a painstaking process in such a tight space.

If you can imagine how some people might keep lots of junk

in their attic,

this space underneath the floor basically resembled that.

There was loads of junk, bits of furniture, lamps, books,

paperwork, magazines, suitcases.

That sort of stuff was underneath that floor along with the body.

The body was concealed underneath a lot of that.

So we had to do a very staged approach to the examination

of removing every layer step by step and documenting that stage by stage

for the police and, obviously, future at court,

before we could even get to the body.

In itself that took some time.

She was only wearing a red dressing gown at the time

and no underwear and the dress was slightly rucked up,

exposing the lower half of her body.

We then go on to examine and take samples of the body in situ,

because sometimes that can be really important

because when you start to move a body,

especially when it's in the process of decomposition,

you start to get further spillage of bodily fluids

through the natural process of decomposition.

I suspect the body's been there for about four to five days.

It was a long September Weekend.

It was very warm, as well.

There was an element of deterioration there

which made it more difficult for the scientists

to obtain material to work with.

It's not a very pleasant situation where you've got a dead body

that you're in a confined space with.

Amanda's forensic examination took over four hours

before the body was removed from under the floorboards,

then placed in a body bag.

But she had not found any obvious external injuries on the body.

A postmortem was carried out

and we were never able to establish the cause of death.

So we don't really know exactly what went on in that house,

who was responsible for physically killing Carol.

The only people that know that are Harry and Rita.

For whatever reason, the pathologists, the scientists,

toxicologists couldn't tell us how she died.

We suspected that she may have been drugged,

poisoned and that's ultimately what caused her death.

Perhaps it's being suffocated, even strangled, as part of that process,

but we were never, ever able to find out exactly how she died.

As you can imagine, in a case like this,

where the police have no information

how that body's come to be under the floorboards,

there's pressure for us to, as quickly as possible,

examine these items to help them with their enquiries

and provide that crucial DNA evidence

to either charge somebody with the crime

or, for the family, to find out what's happened.

Police trawled CCTV footage

and discovered Harry and Rita at St Andrew's bus station in Edinburgh.

Holding hands, they wandered over to the bus stances,

oblivious of the police search of their home.

They boarded a bus to Dundee.

Meantime, Harry's eldest daughter

Susan had contacted her father

on his mobile phone.

Harry told her he was with Carol

and that he was coming back to Edinburgh.

When Phil Gachagan heard the news, he now knew Harry was lying,

and lay in wait for him.

When Harry pitched up back in Edinburgh with Rita

the two of them were detained.

Both of them gave conflicting stories about what happened

during their interviews.

Harry Jarvis, he maintained that he loved his wife

and that he wouldn't have done her any harm.

He claimed that she'd died of natural causes

and he put her body under the floorboards

because he couldn't bear to be without her.

Rita claimed that she and Harry were together as a couple

and that they wanted to leave the area to start a new life together

and that he needed to leave Carol,

and she knew nothing about what happened to Carol.

She said that she didn't know that Carol was dead.

Harry claimed not to be in a relationship with Rita.

That she was just a friend that he was looking after

and he'd given her some accommodation

for a short period of time.

Phil Gachagan knew there would be huge media interest in the case

and it was his very first murder in charge.

I think the pressure that I felt more was the pressure not to fail.

There were four children there

who were desperate to know what happened to their mum

and who clearly wanted justice for their mother.

Amanda recovered evidence from under the floorboards

that would prove vital.

A large piece of parcel tape that had been wrapped around something.

When we examined that back here in the laboratory,

we found not only blood but skin flakes from multiple sources

on the tape with DNA profiles matching that of Carol,

of Harry Jarvis and Rita Heyster,

as well as other fragments like fibres and skin as well.

So, it was a great source of forensic evidence and biological evidence.

Next, Amanda conducted a thorough search of every single room

in the house and made another important discovery.

We found a roll of tape that was in one of the bedrooms,

and this was similar to the parcel tape

that we found underneath the floorboards with the deceased,

and when we recovered that and examined that

back at the laboratory, we were able to find some sources of DNA

from Harry Jarvis and Carol Jarvis and Rita as well.

We also examined that piece of tape.

It had a cut end but also a pulled end,

and then when we opened that up and compared it with the piece of tape

that was found on the body, we found that it was a physical fit

and a direct match from the piece of tape that we found with the body.

It's one of the most eagerly-awaited telephone calls, in fact, as an SIO,

when the scientist calls you

to give you the results of some of the tests.

It's good to know that we have evidence and we've got a DNA profile,

but also to have matches, to say who that DNA may have come from

is something of a feat in itself.

There's a whole load of circumstances there

which allow us to charge the two of them with the murder.

Then we continue with the investigation thereafter

to build up more of a case.

We conducted further examination work on medical samples

that were taken from Harry Jarvis and Rita Heyster

including nail scrapings that were taken from them at the time

when they were detained.

When we examined the nail scrapes from Rita Heyster,

we found DNA from at least three sources

and we were able to resolve those DNA profiles

to matches not only of Rita Heyster, which is not unusual,

you would expect to find DNA from the swabs the person's been taken,

as well as from Harry Jarvis.

And what was remaining was a strong profile

that matched that of Carol Jarvis.

Couldn't say, scientifically, exactly what the source of that DNA was,

but our opinion was that it wasn't through social contact

or for other means of secondary contact.

Slowly but surely the whole story emerged.

Harry was 30 and Carol only 16 when they first met in London.

Four children later, they moved to Scotland.

Carol was a very slight woman. She relied on Harry a lot.

She loved him dearly. That was quite clear.

The children told me that.

And she was very devoted to him.

Mum, you know, was really in love with Dad

and so she would always look for the best in him,

and, even, you could tell Mum that he was the worst person in the world

and she wouldn't believe that, you know?

Harry was...

He was a bit of a fantasist, to be fair,

he got involved in all sorts of dodgy dealing.

He was arrested by the police a few times for minor frauds

and stuff like that.

He had some affairs over the years and met other women -

vulnerable women.

He fleeced them for whatever he could.

But Carol would always find Harry and they would get together again.

He would come back. A sort of cycle would start all over again.

Over a period of time, Carol became reliant on drugs,

prescription drugs, prescribed drugs,

and Harry became her main carer.

By that time, Harry had met Rita Heyster via an online dating site.

By then the relationship had flourished

and Rita moved to Bathgate to be with him.

Rita had been adopted as a child by Tom Forsyth,

who owned the Jus-Rol bakery company.

So, when he died in his early 50s, Rita inherited nearly ?2.5 million.

She was in her early 20s,

but over the years that money was frittered away

on failed relationships and bad investments.

At the time of this murder, she was virtually penniless.

Unfortunately she didn't have anywhere to live at that time,

didn't have any money

and Harry, bizarrely, accommodated her in the garden shed.

Nobody knew at that time that Rita was staying in the shed.

There were rumours in the local community

but nobody reported it to the police.

So it was a real surprise

when we found out that there was this woman living in a shed.

I was told there was a summer house,

and I went round to the rear garden and I discovered that it was a shed,

and not a great shed, at that.

So, not only have you somebody living above the locus

but there's also people living in an address adjacent

and this shed is directly next to next door's patio

where they would maybe sit of a nice evening

and enjoy the sunshine while this woman is living in a shed next door.

Also, in addition to that, Harry had a CCTV camera hooked up

looking down on the shed, as well.

And the shed itself wasn't the most robust.

There was a window, and it was broken,

and it wouldn't have made for pleasant living conditions.

Harry would look after her,

bring her her tea, bring her her food.

He would allow her into the house every now and then to use the toilet

and then he would put her back into the shed.

All this time his wife was lying in bed

and unable to, sort of, do anything for herself.

There was a basic futon-style mattress on the floor of the shed.

There was no bed covers.

The only thing that we found was that there was a pillow

with a pillow slip,

and the pillow slip pattern matched that of the design and pattern

of the duvet cover that Carol Jarvis was found in, and wrapped in.

So, bizarrely, what we have here now is Rita living in the garden shed

and Carol in bed.

Harry and Rita, by this time,

have decided that they want to be together.

He has to come up with a way of leaving Carol

and this was when, I think, the plot was hatched to kill Carol.

I don't know why Harry decided that the only way to be with Rita

was to kill Carol.

Yes, he could have left Carol and been with Rita

if that is what he wanted.

I think, though, over time, over the years,

Harry had left Carol on a number of occasions to be with other women.

But Carol doted on him and sought him out,

found him and talked him into going back to be with her.

I can only assume that he felt that the only way

that he was never going to found by Carol again was to kill her.

However, there were still a lot of obstacles to overcome

before the case was ready for court.

It took over a year, as well, for it to go to court

because at one point the Crown weren't sure if they could proceed

with the case because of the complexity of it -

the fact that we didn't have a cause of death,

and we didn't really know what happened in that house.

I didn't know if this case was even going to see the court.

Then a serious complication emerged.

A successful appeal in another case,

relating to solicitor access, impacted on the Carol Jarvis case.

The interviews that we carried out with Harry and Rita

were deemed inadmissible.

I thought what had been a fairly straightforward case

turned out to be a very complex case.

Unusually, in this case, both the accused were tried separately

for legal reasons and therefore I not only gave evidence once,

I had to give evidence twice.

Harry Jarvis was the first of the two lovers

to stand trial in March 2011.

The evidence that we had became more important

because we didn't have a cause of death.

But to be able to explain that to a jury

who maybe have no scientific background in very simple words,

to me, as a forensic scientist, my biggest challenge.

Because if I can't produce and present my evidence in court well,

then the whole case could basically fall apart.

Amanda faced five hours under cross-examination over two days.

The police also offered compelling evidence.

We found a number of letters on both Harry and Rita's possession

when we detained them.

It was quite clear from these letters

that Harry was sending to Rita that he was trying to kill his wife.

There's one mention of the drugs not working.

It was taking longer than he thought,

but soon they would be together.

So there was a clear intent there, in my opinion, to kill Carol

and Rita knew about it.

I sat at the back of the court, and the foreman delivered the verdict,

and you could cut the atmosphere with a knife.

We didn't have a cause of death.

We don't actually know what happened in there.

We weren't able to use the statements of the two accused.

So that was something that will live with me as well.

Sitting there, at the back of that court,

not knowing whether the jury were going to deliver

a guilty or a not guilty verdict.

When they came back with a guilty verdict,

that was a huge relief for me.

A huge relief. I felt that I'd done my job

and that I'd delivered that justice for the family.

A very difficult time, obviously, over the last few years

and obviously, although delighted, it's a sad day as well.

It's difficult to say you're pleased because, like Graham says,

obviously you've still lost your two parents, in a sense.

So, no matter what the outcome was going to be,

that was always going to be difficult to comprehend.

But, I think, as relieved or as pleased as you could be

in the circumstances, yeah.

I don't really want to ever speak to him,

and I won't forgive him for it, or anything, so I'm just kind of...

To me, right now, he's my dad in biology and genes only.

He's not, like, my father.

But there was still a second trial to be heard.

In July 2011, it was Rita Heyster's turn.

The second trial was even more punishing for Amanda.

I actually gave evidence over a period of three days

which, for me, is the longest time that I've ever given evidence

in court for a case like this.

It was quite clear that Rita wasn't particularly streetwise.

I think she liked companionship

and I think that's what she sought in Harry.

I don't know if she suspected that Harry had intended to kill his wife,

but she was certainly there at the time that his wife was killed

and clearly she was involved in disposing of the body,

if not involved in the murder itself.

There was no case to answer at court in terms of the murder

but she was certainly convicted of trying to hide the body.

Rita Heyster got four years and six months

for attempting to defeat the course of justice.

I don't think any of us actually believe

that Rita couldn't make her own mind up, at the end of the day.

She still formulated her own opinions.

So, she kind of just went with the flow, and so -

is she a victim? No.

I think the thing that I remember most about this was the fact

that here we had two women who appeared to be devoted to this man.

One who ultimately paid the price and died

and the other ended up in prison because of it, because of him.

That was the thing for me.

The other thing was the four children.

I mean, they've lost their mum in horrendous circumstances,

but they've also lost their dad.

He's been sentenced to life in prison.

Their lives are never going to be the same again.

Today, forensic scientists catch more killers than ever.

The future's very exciting for forensic science at the moment

with lots of interesting developments in the pipeline.

DNA miniaturisation is effectively miniaturising the DNA laboratory,

and it allows us to have a piece of equipment in police custody suites,

and what we'll be able to do is take a sample from someone

who's in police custody, who's been arrested,

and their DNA sample can be run through this piece of kit

and within 90 minutes we'll have a full DNA profile from this person

which can then be searched against any DNA database

and can be seen if there's a match with any outstanding crimes

held on the database.

It's going to take away quite a bit of time with the DNA analysis

and give you more instant results,

and I think it's especially crucial with linking unsolved crimes,

for example, sexual crimes.

If you had someone in who was suspected of a sexual crime,

possibly you could link several crimes on the database to this person

in a matter of a couple of hours,

which in the past, may have taken days.

Even so, cases arise where forensic science

directly influences a police investigation.

On Sunday the 30th April 2012,

a neighbour alerted Tayside police

after disturbing a hooded male intruder

at 63-year-old John Kennedy's home in Mossgiel Crescent, Dundee.

When forensic biologist Barry Mitchell was called in by police,

he discovered a grisly scene.

As we were standing in the vestibule,

looking into the living room, we could see the body of a deceased male

lying on the floor, face down, along the front of a sofa.

The upper part of his body was lying in a pool of blood.

I recall being advised from the postmortem

that there were in excess of 70 stab wounds on the deceased's body,

and, in fact, when I subsequently examined the deceased's fleece top

in the laboratory, we counted more than 90 stab cuts

within that fleece top.

There was no known motive.

There was nothing to suggest that there was any enemies involved.

There was nothing to suggest that there would be anybody

that wanted to do this or had anything against John Kennedy.

So we were absolutely reliant on the skills and the abilities

of our forensic counterparts.

Scene examiners had identified the presence of a glove

within the locus as they went about their recording of the scene,

and it was identified that this glove could well be alien to the locus.

So it was targeted as a priority item for examination.

DNA analysis revealed several wearers.

But in the lab, Barry Mitchell narrowed the suspects down

and even had a name - Michael Nolan.

He hadn't even come into the police investigation.

Such was the significance of this

that it immediately did change the focus of the enquiry.

At that stage, our enquiries were not focused on Michael Nolan at all.

Generally speaking, we'll have an idea as to who is responsible,

but there's absolutely no question

that without the contribution of biologists in particular

this would have proved to have been

a very, very testing and difficult enquiry.

Aware of the forensic evidence stacked against him,

Michael Nolan entered a guilty plea and was sentenced

at Edinburgh High Court

to 17 years imprisonment.

The Nolan case is forensic science at its very best -

naming a suspect before the police.

But what will advances like custody suite technology mean?

The difference between the custody suite technology

and the technology that will be developed at crime scenes

is simply the type of sample.

For a custody suite, you're working with a mouth swab

taken from a person. It's a nice fresh sample.

It's got a lot of DNA in it.

So it's very easy to get a nice single source profile.

However, when you're out at a crime scene,

your DNA sample might not be of such good quality,

and it might contain a mixture of DNA from more than one person.

And that takes a lot more technology

to be able to create a quick 90-minute profile,

and that's where we're heading now,

and that's what we're currently working on.

As we move on, as science develops,

miniaturisation comes in and we're now able to do DNA profiling

with even smaller and smaller machines.

A more exciting development will be the crime scene rapid technology,

because that way you could actually get intelligence

to identify a suspect very quickly, perhaps even at the crime scene,

and at that point the person's still out on the street

and still free, and not in police custody.

So, to me, that's the one that will make the huge difference.

The research and development in forensic science

allows us to develop technologies

that make forensic science a very powerful tool,

and it means it's very hard to get away with murder.

This includes unsolved historic murders

that go back for several decades.

So, a suspect could be identified instantly.

It's becoming almost impossible to get away with murder.

Subtitles by Red Bee Media Ltd