Rescuers hunting Mail columnist Michael Mosley were last night focusing on a treacherous mountain path.
After a day that saw divers, coastguards and fishermen scouring the sea, the search for the renowned health writer shifted back to land.
Greek police are now working on the assumption that the 67-year-old diet guru took a disastrous wrong turn as he walked back to his friends’ home on the tiny holiday island of Symi.
One rescuer said the search was becoming a ‘race against time’ as it entered a fourth day.
The mystery of what has happened to the father-of-four, familiar to millions through his newspaper column, TV work and books, deepened yesterday as CCTV showed him wandering through a port town after leaving his wife, Dr Clare Bailey, and friends at a beach.
Dr Mosley was seen dressed in a blue shirt and shorts resting a purple umbrella on his shoulder to shield himself from sun as he strolled past a cafe less than half an hour after telling Dr Bailey he would walk back to their accommodation.
The confirmed sighting indicated he had made it away from the coastal path making it less likely he had fallen into the water.
Later on, after another possible sighting, officers turned their attentions to a mountainous strip of land between the port of Pedi and the holiday home he was staying at in Symi town.
‘It is the first solid lead we have and the entire weight of the search is now shifting to that area,’ a police official said.
‘He probably lost his way and ended up in this windy, uncharted path that links the two regions of Pedi and [Symi town], winding through a craggy mountain.’
It comes as the British doctor’s four children flew out to Greece to help solve the mystery that has baffled locals. Dr Mosley and his wife landed on the 25-square-mile island on Tuesday and were due to stay for a week with a couple who have a holiday home there.
The following day, the group got a boat-taxi to Saint Nicholas Beach. Dr Mosley had a swim before setting off in 37C (98F) heat along a well-trodden coastal path to Pedi at around 1.30pm.
Police understood he planned to take a bus from the small port town back home – but he never made it.
Officers have retraced his steps, going door to door and speaking to businesses and homes along the path he’d taken.
They managed to recover CCTV pinpointing Dr Mosley at Kamares Cafe in Pedi at 1.45pm.
Dr Bailey confirmed it was her husband and officers used the distinctive description to match another sighting at nearby Blue Corner cafe at 1.52pm.
But the trail ran dry with search teams trying to determine if Dr Mosley could have taken a bus, a boat or continued on foot.
Then officials received a possible sighting that placed Dr Mosley heading towards a treacherous path at the edge of Pedi’s small marina at 2pm and scrambled search crews to the area yesterday evening.
It appeared instead of turning off down the main road to Symi town, he may have instead mistakenly followed Pedi marina round and out towards the sea before trying to cut across the peninsula taking a dangerous, craggy route.
‘Even a mountain goat wouldn’t get up there,’ a senior police source told the Mail.
One of the rescuers said any decision to follow the path was ‘inexplicable’.
She said it would have taken a fit young person three hours to walk to his destination. ‘The path is not easy to follow, if he took a wrong turn, he would be lost,’ she said, adding: ‘He could be anywhere. It is a race against time.’
The search was called off at 8pm Greek time as dusk fell and will resume this morning.
Police were last night searching for more CCTV along the marina with some seen making inquires as far out as Agia Marina – right on the sea. It is feared he may have ‘slipped, tripped, fallen’ or even been bitten by a snake.
It came as Dr Mosley’s children – Alexander, Jack, Daniel and Katherine – flew out to retrace his last known steps.
Dr Mosley’s brother, Arthur, told The Telegraph: ‘We are very shocked and perplexed by what has happened to him.
‘We know as much as what the police and the media has reported, but we are closely following the situation, and hope that there’s a good outcome.
‘Unfortunately, when you get to my age or his age, accidents like this can happen.’
Arthur, who lives in the Cornish village of Flushing, said when he last spoke to his brother he had been in ‘good spirits’ and was looking forward to his Greece trip. He added: ‘The family are naturally hoping for a good outcome.’
Locals on Symi have been left stunned at the disappearance.
‘The place is very small,’ Antonis, who has lived on Symi all his life, said. ‘A little kid can’t get lost here. How does a man get lost?’
Firefighters, police, drone and search dogs joined the hunt with Mika Papakalodouka, 20, whose father, Eleftherios, is the mayor of Symi, saying teams were ‘out all night’.
She added that lots of residents had been joining the search using their own boats.