Police on Thursday launched a criminal investigation and arrested a Vietnamese man accused of abusing a Cambodian child.
Nguyen Thanh Dung, 34, will face legal proceedings in accordance with Vietnamese laws.
Vietnamese police would request Cambodian authorities to provide documents and evidence of the case, they said.
Dung and three other men, two Cambodian and one Dutch have been linked to the torture and rape of a 2-year-old boy. Videos circulated on Facebook in early December show the boy naked and being assaulted with an electric prod.
The assault allegedly happened at a local plantation in Cambodia. The victim's parents worked and lived there.
After the videos were posted on Facebook, the Cambodian suspects were taken into custody while Dung fled to Vietnam and was arrested on December 7.
Police said Dung had admitted to the abusive acts.
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