A massive air and land search for a toddler missing for four days in a hamlet in the French Alps has been called off, with investigators saying the focus will now shift to the evaluation of evidence already gathered. The two-year-old boy, named only as Émile, was staying with his grandparents when he went missing on Saturday. He was last seen by two neighbours walking alone on a street in the tiny village of Haut Vernet. Local prosecutor Rémy Avon said in a statement on Wednesday that the massive search had not yielded any clues to solving the mystery of the boy’s disappearance, and no more search parties would be sent out. However, he said, “the investigation into the causes of his disappearance will continue, notably through analysis of the considerable amount of information and elements gathered over four days”. On Tuesday, the prosecutor had warned that “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”. The terrain in the search zone is hilly and craggy with many streams, and the region has been hit by a heatwave, with temperatures of up to 35C (95F) in recent days. Dozens of police officers and soldiers, backed by dog teams and a helicopter, had searched 30 buildings, 12 vehicles and 12 hectares of terrain around Haut Vernet, as well as interviewing 25 people. The site has been off-limits to outsiders since early on Tuesday. Police, still hoping for a breakthrough thanks to witness statements, have circulated a picture of the blond and hazel-eyed boy who was wearing a yellow top, white shorts and hiking shoes the day he disappeared.