Villagers found the dead animals on Thursday (May 30, 2012) in a government-owned PTPN oil palm plantation in Pante Labu village of Birem Bayeun subdistrict in the area. They were estimated to be four and five years old, local environmental group Fakta said over the weekend.
"We suspected that they died after consuming bars of soap laced with poison we found near the carcass," the group's chief Rabono Wiranata told The Aceh Globe.
"It seems that the elephants have died around one week," he added.
The animals are usually either killed by villagers, who regard the beasts as pests that destroy their plantations, or by poachers for their tusks.
Early last month, two other Sumatran elephants were found dead in the Aceh Jaya district in western of the province.
There are fewer than 3,000 Sumatran elephants remaining in the wild, according to the International Union for Conservation of Nature, marking a 50 percent drop in numbers since 1985.
WWF changed the Sumatran elephant's status from "endangered" to "critically endangered" in January, largely due to severe habitat loss driven by oil palm and paper plantations.
Conflicts between humans and animals are increasing as people encroach on wildlife habitats in Indonesia, an archipelago with some of the world's largest remaining tropical forests.