Two Mother Nature activists arrested after filming suspected sand-bearing vessels have been charged with incitement and making unauthorised recordings of a person in “a private place” – an offence that drew scepticism yesterday, given they were in their own boat in the open ocean when capturing the footage.

The activists, Dem Kundy and Hun Vannak, were seized in their boat off the coast of Koh Kong province on Tuesday, about 10 kilometres from where they had been filming the ships, according to the driver of their speedboat. The pair were charged yesterday by the Koh Kong Provincial Court.

Court spokesman Un Sovan Theany described the charges as one count each of violation of privacy and incitement to commit a crime, though he declined to name the crime the pair had allegedly incited.

“The investigating judge decided to put them in prison to keep them to continue the investigation,” Theany added.

Incitement carries a maximum sentence of two years, while violation of privacy – described in the Criminal Code as “recording the image of a person who is in a private place without the . . . consent of the person” – carries a maximum sentence of one year and a fine up to $500.

Following his arrest, Vannak posted on Facebook that the vessels they were filming were about 4 kilometres from ruling Cambodian People’s Party Senator Ly Yong Phat’s special economic zone in Kiri Sakor district’s Prek Ksach commune.

Mother Nature founder Alex Gonzalez-Davidson yesterday said the activists were between 500 metres and 1 kilometre from the ships they were filming, which were suspected to be ready to transport silica sand.

Mother Nature on Monday published a video online exposing huge discrepancies in silica sand trade figures with Taiwan, highlighting more than $30 million in undocumented and potentially illegal exports, according to the group.

The revelations follow similar scandals with sand exports to Singapore and India.

Gonzalez-Davidson said the ships appeared not to be broadcasting an Automatic Identification System signal, meaning they did not show up on online ship tracking databases. “This [arrest] is likely in retaliation for the excellent work the two guys have been doing exposing the corruption and systematic fraud behind the extraction and export of sand,” Gonzalez-Davidson said, calling the charges “completely baseless”.

Vannak and Kundy have both been arrested before in connection to their activism.

Speaking on condition of anonymity yesterday, a provincial police officer said the violation of privacy charge had been brought by Yong Phat, though the policeman said he believed the charge was not relevant. “They did not affect the company’s land because they took the pictures from a boat.”

Yong Phat’s representative did not respond to a request for comment.