One of the last "giant tusker" elephants named Satao II was killed by poachers Monday at Tsavo national park in Kenya, according to a conservation group that protects the nearly endangered group of Africa's oldest elephants.

The Tsavo park rangers found Satao II's body along the border of the national park while they were on their routine checks in the morning. The park, which measures 16,000 square miles, makes it difficult for the rangers to patrol the entire area efficiently every morning. Last month, two rangers were killed while they tried to restrict poachers from entering the park.

When they found the body, it was implanted with a poisoned arrow. The authorities in the park believed that Satao II died of that arrow, however, his cause of death has not been confirmed yet.

Fifty-year-old Satao II was named after another famous giant tusker elephant who was also killed by poachers in 2014.

"Luckily, through the work we do with the Kenyan Wildlife Service (KWS), we were able to find the carcass before the poachers could recover the ivory," Richard Moller, head of the Tsavo Trust, told Agence France-Presse.

"This particular elephant was one that was very approachable, one of those easy old boys to find. Many are the others are much more difficult to see. He has been through lots of droughts and probably other attempts at poaching," Moller added.

According to the wildlife authority, the incident happened just two days after a KWS officer had been killed at the hands of poachers while trying to restrict them from entering the park. A similar incident involving the killing of an official also occurred a month earlier, the authorities told AFP.

After Satao II's body was discovered, the authorities at the park caught an "elephant poaching gang" deep inside the boundaries of the park and arrested two poachers. Twelve poisoned arrows, three bows and an AK47 rifle along with other items were found with the poachers, BBC reported.

"Although this is a very sad loss in everyway, we can take some positive from this in that Satao's carcass was indeed found with the ivory intact, and recovered before it could fall into the wrong hands and further fuel the illegal ivory market. More importantly, this poaching gang... has been broken forever," the Tsavo Trust told BBC.

Moller told AFP that one of Satao II's giant tusks weighed 51.5 kg (112 pounds), and the other 50.5 kg (111.3 pounds). Of the 25 remaining "giant tuskers" in the world, about 15 reside in Kenya, he added.