Original subtitles

(man) 'When a murder's committed, it's always a race against time

to find the truth, to separate fact from fiction,

to catch the killer and to make sure that justice is served.

But what happens when the truth vanishes with the victim?

I'm Dr Richard Shepherd, a forensic pathologist,

performing nearly 23,000 autopsies,

'including on some of the most high-profile cases of recent times.'

I've learnt that the dead don't hide the truth and they never lie.

'Through me you'll be hearing directly from the victim.

From a state-of-the-art laboratory, with ground-breaking technology

that uses digitally scanned sample bodies.

I'll be investigating a series of intriguing murders,'

where from the victim's bodies,

'I'll be revealing to you the truth behind those horrific crimes.'

(camera shutter clicking)

(phone line ringing)

(woman) 'Hertfordshire Police. How can I help?'

(man) 'My partner has been missing since Monday

and not contacted anyone,

so we just decided we should report it.'

'What's your partner's name?' 'Helen Bailey.'

Royston in Hertfordshire is not the place

where well-heeled women in their 50s vanish.

'So, it was a surprise when Helen Bailey, a renowned children's author,

was reported missing from home.'

She'd last been seen walking her dog on t11th April, 2016.

'But why would someone who seemingly had it all'

and who was planning her own wedding, suddenly disappear?

'Could I take your name, please?' 'Ian Stewart.'

'We'll be in contact shortly, OK?' 'OK, thank you.'

People that knew Helen Bailey, her family and friends,

describe her as this very warm, very kind person,

but also someone who was very witty, very funny,

with a wicked sense of humour.

There we go, ready?

(man) 'She was a hugely successful author of teenage fiction.'

The neighbours where she lived said she was friendly, very open.

Invited everybody round for coffee and cake when she moved in.

Very down to earth.

There he is. You can see that he does exist.

Oh! Ha! That wasn't supposed to happen!

(Richard) 'But Helen had been through terrible heartbreak.

Her marriage of 15 years to John Sinfield had ended in tragedy.'

Helen's husband, John, died very suddenly.

He drowned whilst they were on holiday in Barbados in 2011.

(Sam) 'He was in the sea.'

She heard him calling for help.

She saw him disappear under the waves and he sadly drowned.

It must have been horrendous for her to go through that.

Almost unimaginable.

Helen started a blog online called Planet Grief.

'She talked about the kind of the difficulty

of dealing with really everyday things,'

like buying a single Scotch egg in the supermarket

or taking out the bins on your own, week after week,

and how lonely that made her feel.

Writing the blog was dealing with her grief

and reaching out to other people going through the same thing.

She was able to turn her own experiences of grief

into something funny

and something that other people could take great comfort in.

That was because of the kind of natural warmth

'that Helen Bailey had.'

Real life after death is far more bizarre, more complicated,

and quite frankly bonkers than any fiction plot

'that I could come up with.

'For many of us, this reflecting on our relationships'

is part of the process of bereavement.

(Richard) 'Then, in October that year,

eight months after her husband's death,

Helen met someone through an online support group.

He was a widower by the name of Ian Stewart.'

Helen met Ian online.

They were both part of a bereavement group

and that's how they came to know each other.

So, he himself was widowed in 2010.

He had two sons, at that time, would have been teenagers.

So shared experience with Helen Bailey, both of them widowers.

They'd have had a lot to talk about.

I introduce you to my new book,

which is called When Bad Things Happen In Good Bikinis,

subtitled Life After Death And A Dog Called Boris.

Helen spoke about meeting Ian in her blog

and also in her book.

She referred to him as her gorgeous grey-haired widower.

'At the end of her book,

she talks about having found her happy ending with him.'

(Richard) 'The fact they've both lost a spouse seemed to draw Helen to Ian.

Before long, they moved into a house together

in the Hertfordshire countryside.'

Helen Bailey and Ian Stewart

bought a very large house together in Royston in Hertfordshire.

It was worth £1.5 million, decent amount of land around it

'and Ian Stewart's two sons moved in with them as well.'

(Richard) 'After four years together, they were planning their wedding.

But then on 11th April, 2016,

Helen suddenly and inexplicably disappeared.'

Helen had been googling wedding venues

because Ian and Helen were planning to get married.

'All of the people that knew Helen

said it was completely out of character for her to disappear.'

Her friends and family were becoming very concerned.

They'd said they couldn't get in touch with her

and at that point Ian reported her missing to police.

(phone line ringing)

(woman) 'Hertfordshire Police. How can I help?'

'My partner has been missing since Monday,

and not contacted anyone, so we just decided we should report it.'

'What's your partner's name?' 'Helen Bailey.'

'Did she say anything unusual?'

'Nothing before I went out, no.

She asked me to run an errand after I had been to the doctors.'

In the 999 call, given that this is four days

after he's last seen his fiancee,

he sounds incredibly calm, almost to the point of nonchalant.

'What's her height?'

'Oh, I'm going to guess it. She has told me. Probably 5' 10".'

'And her eye colour?'

'How do you forget these things?'

He's almost making light of the situation.

I think he says he can't remember the colour of her eyes.

It doesn't come across as a man whose fiancee is missing,

'who knows what has happened to her.'

'And what sort of build?' 'Slim.'

'She's is slim.'

'That's easy.' (chuckles)

'She left a note.

She said something like, "I need space and time alone.

I'm going to Broadstairs."

'In Broadstairs, we've got a cottage down there.'

Ian maintained that she had left a note

saying she wanted some time to herself,

and that he shouldn't contact her.

(Richard) 'Ian Stewart's account

that Helen had gone to her holiday cottage in Kent

didn't necessarily ring alarm bells.'

(Chloe) 'Her dog, Boris, had gone missing too,'

and that was a perplexing part of the puzzle,

and played in to the idea that she had gone off somewhere

with her dog for time on her own

because why would the dog also be missing?

She's got her mobile phone, she's a got vehicle,

she's got a whole array of support around her.

Could she have gone away for a short time on her own?

The answer is yes.

'Would she be happy going up to someone and asking for directions?'

'Yes, she's very good at talking to people.'

However, she would be leaving a foot print.

She'd be leaving a footprint by the movement of her vehicle,

her mobile phone, a contact on a computer.

If she'd gone on the Tube or a flight out of the country,

she would be recording a bank transaction:

buying a coffee, getting tickets or whatever.

But there was no transactions by Helen on her bank account.

'Leave that with us. We'll be in contact with you shortly, OK?'

'OK. Thank you.' 'No problem. Thank you.'

'OK, bye-bye.' 'Bye-bye.'

(Richard) 'With no sign of Helen a week after reported missing,

officers from Hertfordshire Police Major Crime Team

interviewed Ian at the house.'

That's where an investigation would start,

with a person who'd last seen them alive.

The time, the place, the location.

It's at this point where things start to begin to build up.

'Ian Stewart was not supportive. He was not helping in any way.'

So, that's where the concerns first start to begin to surface.

The note, allegedly made by Helen, could not be found.

That would be a vital clue as to what's happened to her,

but it couldn't be found.

Police had searched the property at the time.

Didn't find her. Didn't find where she'd gone. Unexplained.

(Richard) 'For three months, no sign of Helen.

No one had seen or heard from her, and no answer on her phone.'

Even bizarrely, he went away on a holiday for two weeks to Spain,

whilst all this is going on.

Now, is that the actions of someone who really cared for his partner?

Is that the actions of an innocent man? Don't know.

(Richard) 'With no leads, police went back to the house again.

This time with a specialist search team.'

Three months down the line, a neighbour has tipped off officers

that there's a cesspit at the house.

(Richard) 'The first time police had searched,

Helen's Jeep had been parked on top of the entrance to the cesspit.

But this time the car had been moved

and in amongst the human waste, police made a grim discovery.'

Police found Helen's body hidden in human excrement

in the septic tank beneath the garage at her house.

But she was not alone in that pit.

With her was her beloved dog and a pillow case.

After three months in those conditions,

decomposition can be well advanced.

It affects first the skin.

The skin begins to become sodden and soggy and to fall off.

Eventually, the underlying muscles are affected, too,

and that can make a postmortem examination really quite difficult.

It can eventually result in skeletonization of the whole body.

In this case, decomposition had progressed to the point

where the Home Office pathologist couldn't be sure

whether Helen was alive or dead when she entered the septic tank.

But what he could say with certainty

was that she didn't get there through natural causes.

(Andy) 'There's no way she climbed in there on her own.

Someone has put her in there.'

She was murdered, brutally.

(Richard) 'On 15th July, 2016,

police found the body of the missing children's author Helen Bailey,

in the septic tank beneath the garage of her house.

The entrance had been hidden under a car

and was only discovered after a tip-off from a neighbour

three months after Helen went missing.'

Dealing with the actual recovery of the body,

that would have taken a number of days.

It would need careful extraction of the fluid

from inside the septic tank,

and then excavation in and around the actual tank itself,

and then people going into that tank and removing the body.

No matter how many murders you've dealt with,

to deal with that would be horrendous.

The body was showing evidence of significant decomposition,

after a period of about three months

immersed in this excrement.

A postmortem in that condition can be extremely difficult.

What's surprising is that some significant organs,

like the colon and sometimes skeletal muscle

can be so well preserved, they can be thoroughly examined.

'The secret of what had happened to her was still hidden in her body.

But how she had ended up in there had to be answered.

Her fiance, Ian Stewart, was the last person to see her.'

(woman) 'When was the last time you saw her?'

'Monday afternoon, before I went out,

about quarter to three, twenty to three.'

'She's definitely not at home, no?'

'No. I've literally checked everywhere.

We have got quite a large house, but I've literally checked everywhere.'

In the early stage,

he's a person of interest, as opposed to a suspect.

You're going in with an absolute open mind.

You're trying to find information

and ask questions about her movements, his movements,

in an effort to find out what's happened to her.

(Richard) 'Police examined hours of CCTV footage

and tracked Ian's movements from the day Helen went missing,

when Ian was seen getting rid of items

that included what looked like a duvet.'

Your fiancee is missing and you're at the local tip.

Why would it happen to be the same day that she was last seen alive?

(Richard) 'They then started taking a closer look

at the couple's finances.'

Helen was a very successful children's author.

She was wealthy in her own right.

Ian's sons always said that money, as far as they knew,

had never been an issue for their dad either.

(Richard) 'Helen had recently changed her will,

making Ian her main beneficiary.'

Ian didn't work himself

and Helen was concerned that if anything happened to her,

he wouldn't have means to support himself.

She made him the sole beneficiary to her estate,

which is in excess of £3 million.

There was also a huge life insurance payment

that he would be in receipt of, should she die.

(Chloe) 'On the day Helen went missing, 11th April,'

Ian Stewart logged on to her bank account

and changed a standing order

'going from her bank account to their joint account,'

from £600 to £4,000.

(Richard) 'But despite this suspicious activity,

it was only when he body was recovered from the cesspit

and samples were sent for toxicological analysis,

that it revealed the truth about her death.'

Not much of Helen's body remained after three months,

but the toxicologists were able to identify zopiclone.

Zopiclone is a powerful sedative.

It's only available on prescription

and it's usually used to treat insomnia.

This was present in samples taken by the pathologist at the autopsy

from the colon, which is the large bowel sitting in the abdomen.

Also from muscles present in her thigh

on the front of the upper leg.

Also present was Helen's hair.

Hair is made of keratin, the same chemical

that's used to make fingernails and toenails.

It's incredibly resistant to decomposition.

Hair can also be the pathologist's friend

because we know how fast it grows.

About a centimetre per month in life.

And in to the hair is incorporated,

all the drugs and chemicals present in the body.

So, it can act as a record and a timeline

for things circulating in the blood.

And the toxicologists report showed

'that Helen had been exposed to zopiclone

for several months prior to her death,

and at increasing concentrations.

Now, Helen didn't have a prescription for the drug zopiclone,

but someone else did.

'Ian Stewart.'

In the weeks before, Helen had done some research on her computer

to research the effects of just feeling drowsy, feeling tired,

'feeling that she needed sleep during the day.'

What is clear in this case,

Ian Stewart had been administering this strong sedative

for several weeks, if not months, leading up to this murder.

(Richard) 'Police also recovered a pillow case from the septic tank,

suspecting Ian Stewart had used it to suffocate Helen

before dumping her body.'

(Richard) 'Ian Stewart was arrested and his true nature came to light.'

Ian Stewart is one of the clearest,

most unequivocal examples of a psychopath

that I think I have ever come across.

He is prepared to do anything

to accomplish the ends that he seeks.

The definition of a psychopath.

(Donna) 'What's intriguing about Ian Stewart'

is that I think the potential to carry out these kinds of crimes

was always there,

but his upbringing, his social circumstances

were such that it was just never necessary.

But the potential, make no mistakes, was always there.

He led the police down the garden path for three months,

watching them conduct a completely futile search for Helen Bailey,

whilst knowing that he had put her body in the cesspit

underneath their garage.

There is no emotion to this man.

So, all he is,

is calculation, strategy, manipulation

to get what he wants.

There's no calibration for the impact on others.

'Everything is done on an intellectual and strategic basis.'

(Richard) 'Ian was charged with the murder of Helen Bailey.

At his trial in January, 2017,

he came up with a bizarre story to explain her death.'

What he told us in court

was that two men called Joe and Nick

had come to the house on the day Helen had disappeared,

and said that they were business associates of her late-husband John.

And the story spiralled from there.

He said he saw them several times, they would come to the house,

they would threaten him, physically attack him,

and that they gave him a phone to contact them on,

and that ultimately it was them that murdered Helen,

and them that put her body in the cesspit.

There were gasps from the public gallery,

as he spoke about this in court.

(Richard) 'The jury didn't believe him.

After a trial lasting six weeks,

they returned their unanimous verdict after just six hours of deliberation.

In February 2017, Ian Stewart was found guilty of murder

and was given a life sentence with a minimum term of 34 years.'

(man) 'A very challenging enquiry.'

The lies and deceit that Mr Stewart offered

during our investigation really did hamper us.

It was difficult to understand Ian Stewart's motivations.

He and Helen Bailey seemed to have a happy life together.

They had a big house. They didn't seem short of anything.

She was planning their wedding. They were going to get married.

He was busy planning her murder.

It was hard to understand what more he could have wanted from life.

The judge said that it was a financially motivated murder.

He did it for money.

You think how callous that he's killed his fiancee.

'He's put her in a cesspit.'

Unimaginable how somebody could do that.

(Richard) 'When Ian Stewart's first wife, Diane Stewart, died in 2010,

no one suspected foul play.'

But after he'd been convicted of the murder of Helen Bailey,

police decided to reinvestigate the circumstances of Diane's death.

This is, without doubt, the most extraordinary case

I've worked on as a news reporter.

(Sam) 'In the interviews, he answers a couple of questions'

and then he's completely silent and shakes his head.

Had he not gone on to murder Helen Bailey,

I don't see why we would have found out the truth

about what happened to Diane Stewart.

(Richard) 'When Helen Bailey

was found in the septic tank at her home,

the court concluded Ian Stewart had drugged and suffocated her

to gain her wealth.

'But Stewart's first wife, Diane, had also died young.'

And when the police realised

that Diane had been married to a convicted murderer,

they decided to start a new investigation

into the circumstances of her death.

'Six and a half years after her death,

could Diane's body still reveal the secrets of how she had died?'

Diane Stewart is loved by everybody.

The kind of person that people would be visiting.

'She had a wide circle of friends.

She worked at the local primary school.'

She loved being part of the local community.

Ian and Diane lived in a leafy Cambridge village

with their two sons.

The neighbours I have spoken to told me

that they seemed like a happy family.

Very quiet. Diane was a very lovely person.

No reason to think anything strange was going on.

Very proud of their two sons.

They were able to do the things that they enjoyed.

All that changed when Ian Stewart

made a 999 call to the ambulance control.

(phone line ringing)

(woman) 'Tell me what's happened.'

'My wife's had a fit. She's in the garden.'

'You need to slow down, OK?'

'She's in the garden. She's unconscious.'

'OK. Are you with the patient now?'

'I'm just going out.'

'Can you see her from where you are?'

Ian's account was that he'd been to the supermarket

to get some things for his eldest son

'who was having a driving test.

Hopefully, they'd be celebrating good news.

They were going to have a celebratory lunch.'

'Is she awake?' 'No, no, she's not awake.'

'Is she breathing?' 'No. I don't think so, no.'

'Check on her, sir, for me, please.'

He says he got to the supermarket. Hadn't got his wallet.

He had to come back home and there he found his wife, Diane,

unresponsive, on the ground.

'I've tried and get her in recovery position, but she just flopped back.

I think she's had a fit.'

'You think she's had a fit?' 'She does have epilepsy.'

'Just bear with me a moment.'

At that time he said that she suffered from epilepsy

and that he believed that she'd had an epileptic fit.

(Chloe) 'He tried to resuscitate her.'

When that didn't work, he went over the road

to try and raise the neighbour, a doctor,

but when he got no response,

he came back and again tried to do CPR on his wife,

before eventually dialling 999.

(woman) 'We need to help her.

I'll tell you exactly what to do next.

Pump the chest hard and fast at least twice per second.'

He was then told by the operator to conduct CPR.

'You need to start this, sir, OK?' 'I've been doing that.'

'Count out loud, so I can count with you.'

'OK. One, two, three, four, five, six...'

'That's it. Well done.' 'Seven, eight. One, two...'

This went on for about nearly half an hour

before paramedics and the air ambulance arrived at the scene.

'One, two, three...'

'Has he stopped? Have they seen you?

Right, OK, you keep doing what you're doing until they're ready.'

Unfortunately, when they arrived at the scene,

there was no sign of life and Diane was pronounced dead.

(Richard) 'Ian told everyone that Diane had died

after having an epileptic fit.

But only Diane's body could reveal what had happened to her.'

Epilepsy occurs when there is uncontrolled activity in the brain

and the brain is the central controlling system

for the nerves through the arms and the legs

and the abdomen and the chest.

When the brain has an epileptic event that control is lost.

There's a total random discharge,

often resulting in unconsciousness and collapse

and sometimes even resulting in sudden death.

That sudden death may on occasions be called SUDEP.

Sudden unexpected death in epilepsy.

About half-a-million people have epilepsy in the UK,

but only about 600 die each year

and most of those suffer

from severe convulsive regular epileptic fits.

'Diane didn't suffer from fits like that.

Diane's death was attributed to SUDEP,'

but, in fact, she hadn't had an epileptic fit for decades.

She kept her epilepsy very well controlled.

This doesn't completely rule out SUDEP as a cause of her death,

but it does make it much less likely.

(Andy) 'They were pushed away from murder right from the beginning.'

The narrative was set by Ian Stewart

that she had suffered an epileptic fit.

'This story was being pushed and accepted'

and it was not challenged.

'Everybody has fallen for it.'

(Richard) 'Any forensic evidence that may have proved otherwise

was destroyed at the crime scene by the paramedics

trying to resuscitate her.'

The difficulty is the 999 call

gets put through to the ambulance control.

The ambulance control have clearly

got to consider the preservation of life

and that's what their main priority was.

'From my perspective, from an investigation perspective,

if a person has died,'

that person themselves becomes a very important crime scene.

The contact, the DNA, the blood distribution,

the movements of the body, the movement of clothing.

All those are very, very important

to help identify what's happened and identify who's done it.

How was that crime scene treated?

Or was it ever considered a crime scene?

Probably not.

(Richard) 'Because there was no suspicion,

only a routine postmortem was carried out

to determine the cause of death.'

A normal hospital postmortem examination

is significantly different

to a Home Office forensic postmortem,

which requires a much more detailed examination of a crime scene,

examination externally of the body,

an examination internally of the body.

Where every area of the body is very minutely,

closely examined at forensic detail.

That's not carried out at a hospital postmortem,

where it's more of a routine looking for a cause of death.

'There is a cost

because a forensic postmortem costs significantly more.'

Her cause of death was recorded

as being sudden death in epilepsy, natural causes.

'You know, that's it, case closed.'

(Richard) 'Diane's body was then released back to Ian Stewart,

who had her cremated.'

The truth is he got away with murder.

(Richard) 'Six and a half years later,

with the case reopened,

Ian's behaviour at the time of his wife's death

was called into question.

There were some concerns about Ian's behaviour

after his wife death.

Some people talked about seeing Ian at the funeral

and describing him as aloof.

Just distant.

Not coming across as a husband whose wife had just died.

Ian Stewart received almost £100,000

both in a life insurance policy and from bank accounts.

(Andy) 'He spent money on an MG sports car.'

And that's not the attitude that you would expect from someone

who's a grieving partner.

Why would he act in that way?

People think psychopaths are clever and to some extent, they are.

They've learnt intellectually how to carry out every role.

So, they're better at carrying out those roles

than people who are doing it from any emotional basis.

But what they're doing doesn't come from any real place

and somewhere along the line that always gives them away.

(Richard) 'Despite all this suspicious behaviour

at the time of Diane's death,

no-one had questioned Ian's account of what had happened.

But he had made one very big mistake.'

(Sam) 'Diane was a very public-spirited person.'

She had a donor card when she died that was found.

She'd requested the parts of her be left to medical science.

Among them were her brain.

He thought he'd covered his tracks.

The body was cremated, but every contact leaves a trace

and that trace was left in her brain that was still in storage.

'My wife's had a fit. She's in the garden. She's unconscious.'

(woman) 'You think she's had a fit?' 'She does have epilepsy.'

'Is she breathing? 'I don't think so.'

'I turned get her in the recovery position, but she just flops back.'

When Ian Stewart's first wife, Diane, died in 2010,

no-one suspected foul play.

It was only after he'd been convicted

of the murder of Helen Bailey

'that the police decided to reinvestigate

the circumstances of Diane's death.

There was a part of her body ready to tell the truth,

no matter how much Ian Stewart had tried to cover his tracks.'

Diane's brain was donated to medical science

and actually it was Ian who allowed that to happen.

It'd been stored in the brain bank over a period of six years.

The option would have been available to refuse that,

but that potentially could have aroused more suspicion.

So that wasn't a risk he would take.

(Richard) 'And Diane's brain would hold the secret

that had been missed during the first postmortem in 2010.'

A first pathologist examined Diane's brain,

but found no evidence to suggest she'd died from an epileptic fit.

However, a second pathologist had looked at her brain

and found alterations.

He found evidence that her brain had suffered

from a prolonged period of ischemia.

Ischemia is where the brain is deprived of oxygen

for a prolonged period of time.

Oxygen gets to the brain, as it does to all organs,

through entering the mouth and nose,

passing down into the lungs through the trachea and the bronchi.

The oxygen's exchanged in the lungs and gets into the blood stream,

goes to the heart, pumped back up the arteries,

running up to the organs, the arms and the legs.

That's how oxygen gets to the brain.

And a blockage in either the blood supply

or the entry of oxygen into the body through the mouth and nose

can cause ischemic damage to the brain.

Now you don't get ischemia in a normal healthy breathing person

and you don't get ischemia in an individual

who's just had an epileptic fit.

So, the pathologist in this case came to the conclusion

that Diane had been deprived of oxygen

for a period of between 35 minutes and one hour

and that she had in fact been suffocated.

Ian Stewart's might've thought he'd gotten away with this,

but his secret was revealed,

only by the examination of the brain,

which was absolutely crucial.

The body itself was the evidence that convicted him.

(Donna) 'When arrested, we see this apparent faux outrage.'

We see this indignation at him being arrested.

Ian Stewart does not think like us.

There is a genuine reaction there,

but it's a reaction of irritation.

It's annoyance at somebody stepping in his way.

(Sam) 'The first paramedic to attend the scene

said there were signs of CPR he'd expect to see if attempted.

He said ribs can pop, ribs can snap.

You'd expect to see some injuries. None of which were present.

You've got the call handler instructing you how to do CPR,

you're not seeing her coming back to life,

you would be giving it everything you'd got,

but the paramedics saw no signs of injury to her body.

Both Helen Bailey and Diane Stewart are vulnerable.

They have child-like qualities.

They're naive. They're trusting.

They are his ideal victims and he will have had a sixth sense.

He will have been aware that they did constitute his ideal victims,

in that they were so different from him,

that in some ways they would not have very readily recognised

the coldness, the calculatedness at the heart of this man,

because it was just so different from who they were.

(Richard) 'In 2019, while in prison serving his life sentence

for the murder of Helen Bailey,

Ian Stewart was charged with Diane's murder.

He denied it, but in court the truth came out.'

So it was tense dynamic in the court room

because of the stakes involved.

There's a man on trial for the murder of his wife.

Their two sons are in the witness box.

Diane's elder sister was there.

They'd all been witnesses for the prosecution

and you're hearing this horrible detail.

They're members of your family that you're hearing about.

What an awful thing for them.

(Richard) 'On 9th February, 2022,

Ian Stewart was convicted and given a whole life order.'

The essential part of this second trial of Ian Stewart

was the first trial, the death of his fiancee, Helen Bailey,

and the two cases were put side by side,

so they could see the parallels.

In both cases, this was a person in a relationship with Ian.

'In both cases, they were home alone together.

In both cases, their consciousness had been reduced

and they were then killed potentially by smothering.'

(Richard) 'The critical evidence was provided by Diane's body.

The analysis of her brain tissue indicated her death

was likely to have been caused by restriction to her breathing

from an outside source.'

Suffocation can be caused in different ways.

Basically, it's blocking the mouth and the nose with the hands

or using something soft, like a pillow or a cushion.

Sometimes the individual will fight back.

May be injuries to the arms as they push against the assailant.

If the assailant sits on them, there may be bruising to the chest.

But none of those injuries, those defensive injuries,

will be present if the person is sedated and unable to fight back.

'It had been established during the trial for Helen Bailey's murder,

that she had been sedated and suffocated.'

The fact that there was no evidence in Diane Stewart's case

that she had suffered the same fate wasn't lost on the jury.

(Sam) 'The jury were out for under two days of deliberation,

in the second trial of Ian,

and they found him guilty of the murder of Diane.

The second time guilty of murder.

He has been sentenced to a whole life tariff,

which means he will definitely die behind bars.

Whole-life tariffs

are not given out that often...

and it reflects the severity of his crimes.

A whole-life order is the most severe sentence

a judge can pass in a UK court.

The perpetrator will go to prison and they will die in prison.

That's how grave, how serious the whole-life order is.

(Sam) 'He's financially very comfortable

and yet he's gone on to murder his fiancee, Helen Bailey.

Why is it that he's done it?'

He doesn't need the money. Is it greed? Something else?

To all intents and purposes, he's got away with the murder of Diane.

Yet he's done it again. Is it arrogance?

I think because he's gotten away with the first one,

it gave him more confidence in the second one.

I really do.

(reporter) 'This is the seven-bed, £1.3 million house'

where Helen Bailey lived with Ian Stewart.

Helen's brother John told the jury

that Helen joked that the cesspit under the garage

was a good place to hide a body.

(Richard) 'Ian Stewart might so easily have got away with murder.

Not once but twice.'

But the bodies of his victims gave up the truth that had been hidden.

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