It's a mystery which has baffled detectives.

Just who is the smartly-dressed pensioner wearing slip-on shoes who decided to head to the foot of the Pennines near Oldham, to climb a mountain after dark in atrocious weather?

And why did he appear to lie down and die just before he reached the summit?

Sgt John Coleman said: “I’ve been doing this job for a long, long time and I have never known anything like it.

"It’s sad really. There might be family who don’t know he’s dead.”

The mystery he is determined to solve surrounds the discovery of the body of a man thought to be aged around 70 on a track close to the summit of Indian’s Head above Dovestone reservoir close to the Peak District on Saturday, December 12.

Starting his journey in London on Friday morning, the unidentified man had taken the train to Manchester before heading to the village of Greenfield, in Saddleworth .

Click here to see what police know about the mystery man's journey so far...

Mystery death of man near Dovestone Reservoir, Greenfield, Oldham View fullscreen

He walked into The Clarence pub at 2pm and asked ‘how do you get to the top of that mountain?’, pointing to a 450metre peak above Dovestone reservoir known as Indian’s Head.

The landlord said the man had a northern accent, but didn't sound as if he was from Oldham.

Concerned, the landlord told the visitor there was no way he could make it back before sunset at 3.30pm. It was cold and the rain was lashing down ‘sideways’ that day.

Undeterred, the man set off. Witnesses spotted him about a mile up the steep track to the summit at 4.30pm. A second witness saw him about three-quarters of the way to the top but he never made it.

The next morning, at 10.45am on a Saturday, a walker found his body laying down on a boggy section of track, face upwards and head pointing towards the summit. His legs were together and arms by his side. The body was in full view.

The indications are that he had simply lay down and died at that spot. There was no sign of a fall or any disturbance.

He was wearing black slip-on shoes, a blue coat and a white shirt with a collar - totally inappropriate clothing for a hike in atrocious weather.

Watch: Mystery of man found dead above Dovestone Reservoir in Saddleworth

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No wallet was found, although he had £130 in cash - all ten pound notes - in his pockets and the three train tickets he purchased the day before.

No documents, scars, marks or tattoos were found on his body, although a couple of teeth were missing. His DNA was checked but no match has been found against a series of databases.

Checks of missing person databases have also yielded no clues as to his identity, and nor have enquires with hospitals around west London.

A post mortem examination proved inconclusive and further toxicology tests are being carried out to establish a cause of death.

Pictures: Mystery of elderly man found dead in Greenfield

Police are determined to solve the mystery and remain open-minded about how and why he made his last journey. Was he returning to a spot familiar from his youth? Was he simply confused? What drew him to Indian’s Head?

“Maybe he lived in the area as a younger man and was re-visiting. What drew him to the area is another line of enquiry,” said DS Coleman.

Police have plotted the man striding with an apparent purpose ‘backwards and forwards’ through Ealing in west London before making his way to Ealing Broadway train station at 9am on the day before his body was discovered.

At 9.07am he bought a ticket to Euston Station where he was seen going to booth three and paying £81 cash for a return to Manchester Piccadilly. It departed at 10am and arrived in Manchester at 12.07pm.

Once at Piccadilly he appeared to be in no hurry, spending about 50 minutes in various shops at the station - including Boots and M&S - buying food.

He then spent four and half minutes at the information counter, although enquires have not established why he spent so long there or what he was asking about.

Then he went to the taxi rank at Piccadilly’s 'rear' entrance near Fairfield Street before coming back into the station and heading out of the station through the front entrance.

Anyone with information is asked to call police on 0161 856 8972 or Crimestoppers, anonymously, on 0800 555 111.

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