Thirteen months after the discovery of a man’s body on Saddleworth Moor and following a painstaking police investigation, the mystery surrounding his identity has been resolved.

A coroner confirmed on Thursday that the man found dead at Dovestone reservoir in Greater Manchester was David Lytton, 67.

In a short hearing at Heywood coroner’s court, the Manchester North coroner, Simon Nelson, confirmed that officers had checked passenger records from a flight from Lahore in Pakistan, which tallied with Lytton’s details.

The mystery of Saddleworth Moor: who was 'Neil Dovestone'? Read more

On 10 December 2015, Lytton boarded a plane in Lahore and travelled almost 4,000 miles (6,440km) to London.

At about 2pm the following day, the “stranger” walked into the Clarence pub in Greenfield, Saddleworth. Tall, white, with receding grey hair, brown eyes and a prominent nose, he asked for directions to the “top of the mountain”, the summit of the 1,500ft Indian’s Head peak above Dovestone reservoir. He was wearing a light mac, normal trousers and a shirt, and slip-on shoes.

A day later, his body was found on a secluded moorland path. Toxicology tests last March confirmed that the pensioner died from a dose of strychnine, a highly toxic odourless alkaloid used as a pesticide, particularly to kill rodents.

He had no wallet, mobile phone or other identification and remained unidentified, despite numerous public appeals and the release of CCTV footage of his last known movements. The story was picked up as far away as Japan and the US. An Australian news website speculated that the man was an international spy.

Facebook Twitter Pinterest Lytton at Ealing Broadway station in London. He had three train tickets in his jacket when his body was found. Photograph: Greater Manchester police/PA

Little is known about Lytton, who laid down fully clothed and was overcome by the elements on the remote hillside above the river Tame.

Only a few bare facts have come to light about the circumstances leading up to his death. Officers checked passenger records from dozens of flights from Lahore and found details that tallied with Lytton’s. They also checked airport and train station CCTV to confirm his movements.

Following the then unknown man’s death, a number of theories were explored and discounted, including speculation that he was a survivor from a plane crash in 1949 near Indian’s Head, the outcrop where he was discovered, which killed 24 people, and he may have made a pilgrimage to the site.

There was also another promising lead. A man from Northern Ireland, Sean Toner, contacted police. His father, Hugh, had gone missing from a Craigavon hospital in 1994 and not been seen since. In photos, he bore a resemblance to the man in the CCTV images. But when a DNA sample was taken from Toner, it proved not to be a match.

But there was one theory that DS John Coleman kept returning to: that the mystery man had links to Pakistan. Police had discovered that Lytton had a 10cm metal plate inserted into his left leg between 2001 and 2015, which indicated that the operation had taken place in Pakistan. A container of medicine found on his body was also linked to the country.

On the first anniversary of his death, police had a major breakthrough.

Speaking to the Guardian, Coleman said: “We started to concentrate on the Ealing area and looked at the train lines and where they travelled to.

“We already knew that this man had an operation in Pakistan in the last 10 years and we started looking into the theory that he could possibly have travelled alone from Pakistan to London Heathrow in the days leading up to his death.”

This began a process of trawling through hundreds of names of people who had boarded flights in the days leading up to 12 December 2015.

“The check of the flight names threw up a particular name. We then managed to get a passport for that gentlemen, and although the picture was old, it looked right,” he said.

Police then sourced CCTV footage from Lahore airport, which showed Lytton boarding a flight. Further CCTV footage showed him arriving at Heathrow airport. These were the crucial parts of the jigsaw.

“They were an extremely close resemblance to Neil Dovestones [a nickname for the man] and we actually got this imagery exactly a year later on the anniversary of his death. Then we were able to trace a relative who provided us with a DNA sample,” Coleman said.

This DNA sample from a white British relative led to a positive identification. Lytton from London had been living in Pakistan for 10 years before returning to the UK and heading to Saddleworth for reasons which still remain a mystery.

At the brief inquest in Rochdale, listed in the name of Neil Dovestones – a nickname reportedly given to him by mortuary workers at Royal Oldham hospital – Nelson said a full hearing would take place at Heywood coroner’s court on 14 March.

In January last year, pictures of Lytton were circulated to GPs nationwide, while detectives from Manchester travelled to London and visited hostels, hotels and pubs in their quest to uncover his identity.

Officers identified the smartly dressed man in CCTV footage from Ealing, west London, where he is believed to have started his journey on the morning of 11 December. He arrived in Manchester shortly after midday, having taken a train from London Euston, then went to Greenfield.

Despite being warned about treacherous weather conditions by the Clarence landlord, Mel Robinson, the man left the pub and was spotted by witnesses walking up the hill at about 4.30pm. His body was found the next morning by a passing cyclist on a boggy section of track at about 10.30am.

He was lying on his back, 700 metres down from Chew reservoir. He had walked a little over 4km, much of it uphill. His arms were at his sides, his feet facing downhill. He had £130 in £10 notes in his right trouser pocket. In his left coat pocket were three train tickets from the previous morning: a single from Ealing Broadway to London Euston and a return from Euston to Manchester Piccadilly.

Also in his coat pocket was a medicine box made of card. Inside was an empty container labelled thyroxine sodium, a drug produced by GlaxoSmithKline for the treatment of hypothyroidism. The label was printed in English and Urdu.