The prime suspect in a disturbing child abuse case in Mondulkiri was apprehended by Vietnamese police in Saigon yesterday evening, according to James McCabe, director of the NGO Child Protection Unit (CPU).

Vietnamese national Nguyen Tangdung, 25, is believed by police to be the man seen physically abusing a young boy in a video widely shared across social media on Tuesday.

“He’s the primary suspect for the horrific video that was released,” McCabe said at 9:45pm last night. “I can confirm that Taskforce Uniform has made an arrest in Saigon approximately an hour ago . . . with the assistance of CID Headquarters Saigon.”

Mondulkiri deputy police chief So Sovan confirmed that Vietnamese police arrested Tangdung at 8pm yesterday.

Tangdung’s boyfriend of two years, Dutch national and Mondulkiri plantation owner Stefan Struik, has been assisting police with their enquiries since being arrested en route to Kampong Cham, according to the CPU’s McCabe.

Two Cambodians who were arrested alongside Struik were released yesterday afternoon, according to Kampong Cham deputy provincial police chief Heng Vuthy. McCabe was at pains to stress that neither of the two – who are employees of Struik’s palm sugar plantation – are suspected of any wrongdoing.

A second Mondulkiri deputy police chief, Hang Chansothy, said yesterday that Struik had driven Tangdung to a bus station on Tuesday after a police manhunt began, facilitating his escape across the border to Vietnam.

Chansothy added that Tangdung had used Struik’s phone to film the abuse and upload it to a Facebook account in the Dutchman’s name.

In two of those videos, the man alleged to be Tangdung can be seen giving his young victim electric shocks. A photo of the weapon used to apply the shocks supplied by the CPU showed it to be a DIY taser assembled by driving two nails into the top of an electric mosquito swatter, which is held together by cellotape.

Deputy police chief Chansothy said that Struik will be punished for failing to report the abuse when he first discovered it.

“The Dutch man could have broken the law by knowing about a crime but not reporting it and providing information,” Chansothy said.

CPU’s McCabe sought to dispel rumours circulating on social media that the victim was dead. “That’s incorrect; he’s well, he’s healthy and he’s secure and is receiving assistance from multiple agencies,” McCabe said.