The rhinoceros endemic to Java is one of the world's most endangered mammals, with authorities believing there are around 82 remaining in the wild.

It comes as the government and police reportedly investigate the claims of a captured poacher that a single gang was responsible for the deaths of 26 Javan rhinos since 2019, nearly a quarter of what was the animal's total population.

"The defendant has been convincingly found guilty," the presiding judge told a court in Pandeglang, Banten, adding he would be fined 100 million rupiah ($6,127). 

"He has killed, kept, and traded parts of protected wildlife," the judge added.

The perpetrator, named Sunendi, was convicted of killing the rhinos between 2019 and 2023 in Java's Ujung Kulon National Park. 

Prosecutors had only sought a five-year jail term but court spokesman Panji Aswinartha said the sentence was harsher because Sunendi was also found guilty of arms possession and theft.

Sunendi used an airsoft gun and a pistol to hunt for the rhinos, according to the court's indictment.

"The defendant's action has caused restlessness among the public. He also has enjoyed the fruits of his crimes and he did not have any mercy for the protected wildlife," Panji said. 

Local media reported police have arrested five poachers in recent months and were on the hunt for eight more in connection with the poaching.

Banten police said they were still verifying the claim that the same poachers had killed 26 Javan rhinos since 2019. 

The rare animals have folds of loose skin giving them the appearance of wearing armour plating. 

They once numbered in the thousands across Southeast Asia, but have been hard hit by rampant poaching and human encroachment on their habitats.