French investigators have found the remains of a toddler who went missing last year in an Alpine village in a case that shocked the nation, and are working to determine how he died, a prosecutor said Sunday.

Two-and-a-half-year-old Emile Soleil vanished on July 8 last year while staying with his grandparents. Two neighbours last saw him in the late afternoon walking alone on a street in Le Vernet, 1,200 metres (4,000 feet) above sea level in the French Alps.

"On Saturday, the police was informed of the discovery of bones near the hamlet of Le Vernet," prosecutor Jean-Luc Blachon said. He added that genetic testing had shown they were the remains of Emile.

It marked the first breakthrough in the case.

The prosecutor did not give a cause of death but said that forensic investigators were continuing to analyze the bones, which were spotted by a walker.

The prosecutor added that police were carrying out new searches in the area where the body was found. A roadblock had been set up on the only road into Le Vernet on Sunday.

Emile disappeared the day after he arrived in the village to stay with his maternal grandparents in their second home for the holidays.

The little boy, barely 90 centimeters (35 inches) tall, was wearing a yellow T-shirt, white shorts, and tiny hiking shoes, a call for witnesses at the time said.

A massive on-the-ground search involving dozens of police officers and soldiers, sniffer dogs, a helicopter, and drones failed to find him in July.

A prosecutor said after several days it was unlikely that such a young child would have survived in the summer heat.

  'Family's grief' 

 An initial probe into a missing person soon became a criminal investigation into a possible abduction. The possibilities of an accident or a fall have also remained open.

Police on Thursday returned to the village, cordoning off the area and summoning 17 people including family members, neighbors and witnesses to re-enact the last moments before he went missing to try to solve the mystery.

Drones flew overhead in the drizzle to capture footage of the re-enactment, but there was no news of any major discovery after the exercise.

Emile's mother and father, devout Catholics, were absent on the day of his disappearance.

Until now, some media had focused on the boy's grandfather, now in his fifties.

The grandfather was questioned in the 1990s over alleged violence and sexual assault at a private Catholic school.

But a source close to the case said his possible involvement in the disappearance had always been examined to "the same degree" as other hypotheses.

The grandfather's lawyer on Sunday declined to comment, "out of respect for the family's grief".

In late November, a day before Emile would have turned three, his parents published a call for answers in a Christian weekly.

"Tell us where he is," said the couple, who also have a younger daughter.