CHENGDU, March 30 -- Hesheng, a captive-bred panda, died in September 2016, two months after being released into the wild in southwest China's Sichuan Province, Chengdu Research Base for Giant Panda Breeding announced Friday.

The male panda, born in 2013, had undergone training at Liziping Nature Reserve from March 2016 and was released into the wild in July.

On Sept. 11, Hesheng was spotted safe and well some 3.5 km away from where he was released. Just weeks later, however, on Sept. 27, his GPS collar sent an alarm, prompting an overnight search for Hesheng.

When researchers found his limp body they noticed injuries on his right shoulder, right ear and right hind limb. An autopsy confirmed Hesheng died of septicemia due to a bacterial infection after being attacked by unknown animals.

Giant pandas are among the world's most vulnerable and rare animals, with a known population of only 1,600, mostly in China.