The search for a seven-year-old Japanese boy missing since his parents abandoned him in a bear-inhabited forest was proving frustratingly difficult due to a lack of clues, a rescuer said Tuesday.
As the search continued for a fourth day on Japan's main northern island of Hokkaido, two hunters joined more than 100 rescuers, police and local town officials after they found fresh bear droppings in the area, heightening concerns for the safety of the child.
But they have found no clues to the whereabouts of Yamato Tanooka, who has been missing since Saturday after his parents made him get out their car on a mountain road as punishment for misbehaving.
The parents originally told police their son had got lost while they were out hiking to gather wild vegetables -- but later admitted they were angry and tried to punish him because he had thrown stones at cars and people.
"We just have too little information about how the boy would have acted after being left alone," local fire department rescuer Satoshi Saito told AFP by telephone, expressing frustration at the lack of progress so far.
"He must have been able to walk around himself, but we are having a difficult time projecting which route he would have taken and how far."
The parents told police they abandoned Yamato on a road, bounded on both sides by thick mountain forests, but quickly returned only to find him missing.
On the northern side of the road is a slope of Mount Komagadake, with an altitude of 1,131 metres (3,710 feet).
"Unless he started climbing the mountain, he would have hit a main road after walking for two-three kilometres (1.2-1.9 miles) in any other direction," Saito said, adding that there are no witnesses.
The child was alone in the forest, reportedly with no food or water as heavy rain fell at night.
Footage showed scores of officers clawing through overgrown forest and tall bushes.
The boy was wearing a black jacket, navy blue pants and red sneakers when he disappeared.
Police have said they are considering filing neglect charges against his parents, according to Kyodo News.