On 12 December 2015, the body of an unidentified man was found just off a hillside path beside a reservoir on Saddleworth Moor, a popular walking spot on the edge of the Peak District.
He had taken a fatal dose of a rat poison not available in the UK. He had no form of identification – just some money and a medicine bottle with a label written in English and Urdu.
Police spent the next 12 months piecing together who he might have been, ruling out theory after theory.
They pored over grainy CCTV footage showing his movements the previous day as he travelled from London to Manchester and then to Greenfield, near Oldham, where he asked for directions to the "top of the mountain", a peak known locally as Indian's Head.
Eventually Greater Manchester police announced, after having trawled through flight records and discovered a 10-year-old passport, that the man was David Lytton, had died aged 67, and was a former tube driver from London. He had just returned from Pakistan, where he had lived for almost a decade.
On Tuesday, the senior coroner for north Manchester, Simon Nelson, recorded an open verdict on Lytton's death, putting some of the mysteries surrounding the case to rest.
But there are still several unanswered questions about the man on the moor.
1. Why did he buy a return train ticket?
Lytton had no ID on him, no mobile phone, and no bank cards – for someone to be found with no identifying document on them is almost unheard of in the modern age.
But one thing he did have, alongside £130 in £10 notes in his right trouser pocket, was a return train ticket to London, costing £81.50, bought at London Euston station.
Sometimes a return ticket is more cost effective than buying two singles, but why this should matter to someone who apparently planned to end their own life is a mystery.
We can see from CCTV footage that Lytton spent four minutes speaking to a information office assistant at Manchester Piccadilly station, although it is not known what he was asking about.
Lytton also was booked into the Travelodge hotel in Ealing for five days. He only stayed one night.
2. Why did he spend 53 minutes browsing shops at Manchester Piccadilly station?
After Lytton got off the train in Manchester, he then spent almost an hour looking through the small number of shops at Piccadilly Station. He bought a sandwich at Boots and sat down to eat it. He looked in Marks & Spencer.
He left the station at 1pm and walked in the direction of the city centre.
3. Why strychnine?
One of the first concrete facts to emerge about Lytton's death, other than the time and place it occurred, was that it was caused by taking strychnine, a substance commonly used to poison rats in some countries and people in Agatha Christie novels.
It is a painful and slow way to die: An overdose causes full-body convulsions, leading to suffocation.
Because of the risks, it is illegal to buy the drug in the UK, but it is widely available in Pakistan.
Lytton has been described as highly intelligent and well-read by friends and neighbours, so it is perhaps unlikely that the choice of drug was made lightly.
4. Why Pakistan?
Lytton was described in court as a loner, someone who had very few social engagements. While courteous and polite, his neighbours had little insight into his motivations or why in 2006 he moved to Pakistan, more than 3,500 miles away.
Before moving to Pakistan, Lytton lived in Lilian Street in Streatham, south London. His then neighbour Peter Dias, who still lives there, told BuzzFeed News: "He did have a friend, and I don’t know who this was, who used to visit him and stay overnight on quite a few occasions, and he looked of Indian or Pakistani descent. I don’t know if he followed his steps."
It is highly likely this friend was Salim Akhtar, who told the inquest he met Lytton in the early 1970s and admitted the pair had a "peculiar" relationship, where neither man knew much about the other's private life.
Akhtar said the pair travelled to Pakistan three times and said the lifestyle and weather suited Lytton.
Akhtar also said Lytton never mentioned suicide and that he was intelligent enough to play five games of chess at once.
The inquest heard that Lytton had been having visa problems with the Pakistani authorities and had been imprisoned twice for overstaying on his visa.
5. Was Lytton mourning the loss of a child?
The inquest heard that Lytton had previously been in a relationship with a former nurse, Maureen Toogood, for almost 35 years. He met her when he rushed to help after she collapsed in a street when she was aged 25.
She became pregnant in the 1980s and the couple were happy, but she suffered a miscarriage four months later. The inquest heard that Lytton never fully recovered from the loss.
In a statement read in court, she said: "In the 1980s I fell pregnant with David’s child. He was very attentive to me, he was over the moon on hearing the news, we were aware it was a baby girl. I believed we would get married and our lives would be very different. The pregnancy was not planned but we were both so happy.
"Tragically, I miscarried. However David struggled to cope … he became withdrawn and quiet and I don’t think things were ever the same with us after that."
Lytton suddenly and unexpectedly moved to Pakistan in October 2006. Toogood only found out he had sold his house and moved away three days after he'd left, from a neighbour. In her words, he "vanished into thin air". The next she heard about him was when police called in December 2015 to inform her he was dead.
6. Why Saddleworth Moor? What's the significance of "the mountain"?
When Lytton arrived at Greenfield, a small town in the steep foothills of the Pennines, shortly after 1pm on 11 December, he stopped in a local pub, The Clarence.
He asked the landlord the best way to get to the "top of the mountain", gesturing to Indian's Head, the 400-foot peak beside the Dove Stone reservoir, a popular spot for walkers and hill-runners.
No one locally refers to it as a mountain – it's not nearly tall enough – and Lytton gave no indication of why he wanted to go up there.
In just a simple jacket and slip-on shoes, he was hardly dressed for hill-walking in December.
Detective Sergeant John Coleman of Oldham CID, who led the investigation into Lytton's death, told the inquest of the moment he found the body: "The rain was lashing in the wind was blowing down on the valley. Rain was coming in sideways almost as if there was no gravity. It was extremely cold, not a location I would like to spend time overnight."
Lytton's head was arched backwards, his face pointing up to the sky. "It looked as though he had sat down and just lay backwards," said Coleman.
No one who knew Lytton has yet said that he displayed any interest or knowledge of the area.
Family, police, and neighbours all agree there was no known connection between Lytton and this part of Saddleworth, or even the North West of England.
The biggest question of what haunted Lytton and what drew him to a rainy patch of northern moorland remains unanswered.
Lytton's brother, Jeremy, told the inquest that he couldn't imagine Lytton killing himself: "Although I hadn’t spoken to David for 10 years I can’t imagine any situation that would put David over the edge to want to commit suicide.
"Even though he had the visa problems and had to get out of Pakistan quickly. I can’t believe for one minute that would push him over the edge."