Malaysian wildlife authorities have discovered decomposing remains of another three Borneo pygmy elephants, the latest in a string of unexplained deaths of the endangered animals this month.

Police are investigating suspicions that the elephants were poisoned following the deaths of 10 more elephants earlier this week. Samples from the dead elephants were taken for laboratory analysis after veterinarians said the creatures had suffered severe hemorrhages and ulcers in their gastrointestinal tracts, reports the Associated Press.

Sabah’s environment minister Masidi Manjun said there could be more dead elephants in the Ganung Rara Forest Reserve, where an unknown number of the animals roam.

“There is definitely a sense of urgency,” Masidi said. “We cannot discount the possibility of more bad news”.

The WWF conservation group estimates that fewer than 1,500 Borneo pygmy elephants exist, mostly living in Sabah. The creatures grow to about 8 feet (245 centimeters) tall and are known for their babyfish faces, large ears and long tails.

An orphaned male elephant named “Joe” was transported to a Sabah wildlife park. Officials says it is under observation and appears healthy.