An exhaustive search has found no sign of a toddler missing since Saturday in a tiny village in the French Alps, investigators said, adding that the hunt would continue with more police resources.
There was "no clue, no information, no element allowing us to understand the disappearance" of two-and-a-half-year-old Emile, local prosecutor Remy Avon told reporters on the scene yesterday.
If he was simply lost then "medically, beyond a period of 48 hours, given the child's young age... and the current intense heat ... his life is very much at risk," he added.
Emile was staying with his grandparents when he went missing on Saturday.
He was last seen by two neighbours walking alone on a street of Haut-Vernet, a tiny village of 25 inhabitants at an altitude of around 1,200 metres.
Dozens of police and soldiers backed by dogs and a helicopter had searched 30 buildings, 12 vehicles and 12 hectares of terrain around Haut-Vernet, as well as interviewing 25 people, Mr Avon said.
The site was off-limits to outsiders from early yesterday.
Although "we're pushing on-the-ground investigations as far as we can", including searching haystacks, "we're at the same point as yesterday and the day before," Mr Avon added.
He said that while the physical search would continue today, the investigation would enter "a second phase" of "analysis" of the results of the search.
"We will have to give the police time" to work, Mr Avon said, adding that the number of gendarmes working on the probe had been increased to 20 and it would be categorised as a nationwide investigation, granting access to more resources.
Large-scale searches involving volunteers, which took place on Monday, were discontinued.
Mr Avon had earlier said that as well as the physical search, investigators were also looking at details like local phone records to determine "what phone calls were made, by whom and to whom", around the time of the disappearance, as well as what mobile phones were connected to local towers.
"All possible explanations are on the table, we're not favouring any, and we're not ruling any out," Mr Avon said.
The terrain in the search zone is hilly and craggy with many streams, and the region has been hit by a heat wave, with temperatures hitting a high of 35C yesterday, according to weather authority Meteo France.
The search has focused on an area of 5km around the hamlet.
Police, still hoping for a breakthrough thanks to witness statements, have circulated a picture of the blonde and hazel-eyed boy who was wearing a yellow top, white shorts and hiking shoes the day he disappeared.
Around 1,200 people have called a tip line, but Mr Avon asked people not to overwhelm investigators with possibly irrelevant information.
Hundreds of volunteers have taken part in efforts to find the little boy.
Prosecutors have given no information about the number of adults present in the grandparents' house when Emile disappeared.
