The incident happened nearly two months ago but their carcasses were discovered recently.
The Facebook page for Huai Kayeng elephants in the Thong Pha Phum district posted on Friday that five elephants were found dead in the pond. Their corpses had disintegrated and only their bones were left.
Pichet Chaisawad, the chief of the Lam Klong Ngu National Park, said he had received a report from villagers who had entered the forest that they had found five elephants fallen in a pond.
Lam Klong Ngu National Park staff went to the area and found that the incident had occurred in the Phra Ruesi conserved forest, not the national park area.
Preliminary investigation showed that the five elephants could have been dead for two months. Two of the carcasses were fully grown elephants, one of them was an adolescent and two were baby elephants. They said they could not identify their genders as the corpses had disintegrated beyond recognition.
The park staff and the village headman prepared a memo for the police daily report. They said the pond would be filled with lime mortar.
He explained that the incident might have occurred due to soil collapse. The underground layer was the tunnel from the mine. He said it could be dangerous to animals and humans hence the village should put up a sign to warn people.