Forest rangers in the central province of Ninh Thuan seized the carcasses of 15 endangered monkeys from two poachers during a patrol in Nui Chua National Park on Tuesday.
A team of rangers arrested the two men caught red-handed transporting the eviscerated bodies of the 15 black-shanked douc langurs out of the forest.
Nguyen Xuan Tuan, 37, and Dao Minh Khach, 18, both hail from neighboring Khanh Hoa Province.
The rangers seized a gun and 11 bullets from the pair, who confessed they had shot and disemboweled the langurs before storing them in an insulated cooler.
The poachers were later handed over to local police.
The black-shanked douc langurs (Pygathrix nigripes) and their red-shanked and grey-shanked cousins are found only in the Indochinese nations of Vietnam, Laos and Cambodia.
The black-shanked douc langurs are found in forests in Vietnam and Cambodia. The species is unique among the doucs, having a largely greyish-blue face.
The species is listed on both local and international endangered animal lists.