The death toll of Borneo pygmy elephants in a Malaysian forest has risen to 14, with wildlife officials locating the decomposed remains of the latest victim Wednesday.

In the last three weeks, forest officials have been sighting carcasses of elephants near each other at the Gunung Rara Forest Reserve, in Malaysia's Sabah state on the island of Borneo.

They suspect that the pachyderms may have been poisoned by substances that the workers at nearby oil palm plantations had left to prevent them from eating the palm fruits.

"We suspect poison was spread over the area by plantation workers," the head of the Sabah Wildlife Department, Laurentius Ambu, told The Wall Street Journal. "We are waiting for lab results to determine if the elephants died of poisoning or bacterial infection."

The officials are concerned that more endangered pygmy elephants could be found dead, as these animals roam in groups. They warned that the health condition of a 3-month-old calf that was photographed trying to wake its dead mother is deteriorating, and it is losing weight fast. The orphaned male calf, nicknamed Joe, is reportedly traumatized and has lost 22 pounds after a 497-mile road journey to a Sabah wildlife park, the Star newspaper said.

The World Wildlife Fund (WWF) conservation group blamed the death of the baby-faced elephants for the rise in conflict between man and wildlife, as the forests are being converted for plantations within forest reserves. The group called for protection to all forest areas in Malaysia's Sabah state, a report by The Associated Press said.

According to WWF, there are about 1,500 Borneo pygmy elephants in the world, of which some 1,000 elephants are in the state of Sabah. The conservation group has listed the elephants as endangered.