Rescuers are still on the lookout for Yamato Tanooka, a seven-year-old Japanese boy who went missing since Saturday in a bear-infested forest of northern Japan’s island of Hokkaido. Ground Self-Defense Force, the Japanese army, joined the search for the missing boy with 75 personnel.

The boy’s parents abandoned him in the forest as a punishment for misbehavior.

“The crucial 72 hours’ limit for the survival has passed,” CNN quoted rescue team spokesman Satoshi Saito as saying. “The outlook could be severe … but we can do nothing but continue looking with a hope in mind.” No trace of the Japanese boy has been found till now and the search mission had to be suspended on Tuesday due to thunderstorms.

Takayuki Tanooka, the father of the seven-year-old, said he did not admit the truth about how his son went missing when he first requested the search. The parents initially told the police that their son went missing when they went to gather wild vegetables.

“We have done an unforgivable thing to our child, and we have caused a lot of trouble for everyone,” Tanooka said. “I just hope he is safe.” The rescue team was accompanied by two hunters after two members reportedly spotted bear droppings. However, according to Saito, it was later concluded by the hunters that the droppings came from smaller animals.

The search for Yamato began at dawn on Tuesday and was extended northward to Mount Komagatake, a 1,131-meter (3,710-feet) volcano from the spot where the boy was abandoned by his parents.

According to the officials, the search into the jungle was being carried out at the request of the parents. “We do not think the little boy chose to go into the forest, so we focus on the area along the road connecting from where he was left,” Saito told CNN. He added that the team is having difficulty in determining which route the boy could have taken. Saito said that unless Yamato chose to climb the mountain, he should have reached the main road by walking for two to three kilometers in any direction.

The Guardian reported that Nanae, a local town, requested the military assistance after no trace of the boy could be found even after four days.