A lawyer for 10 foreign nationals arrested last week during a party in Siem Reap confirmed Monday they have been provisionally charged for “producing pornography”.

The 10 include five British and two Canadian citizens, as well as a Dutch, Norwegian and New Zealand national. They were taken into custody from Siem Reap town’s Svay Dangkum commune last Thursday and sent to pre-trial detention on Sunday.

Sourng Sophea, the group’s lawyer, said that his clients had not committed the alleged crime and expected the trial to be held within a month.

They are charged for “production” of pornography under Article 39 of the Law on Suppression of Human Trafficking and Sexual Exploitation, which carries a maximum prison sentence of one year.

Officials have been tight lipped about the circumstances leading to the arrest, but a police report says that anti-trafficking officers went to a house in the commune to “crack down on a case of pornographic pictures and pornographic materials” at an event called “Let’s Get Wet”.

It reports that police officials found used condoms, as well as people drinking and dancing in a sexual manner.

Police say 87 people were detained in the raid, with all but 10 released after being educated about “Khmer traditions and culture”.

The group’s lawyer, Sophea, said the police had not divulged any evidence of the alleged crime and that his clients were only holding a pool party. “They were having a party in their place where there is a swimming pool. For me, just wearing a bikini is not a pornographic activity,” he said.

On a Facebook page for “Let’s Get Wet”, the group advertised a party at a “secret” location held last Thursday. The page also includes photographs and video from past parties, mostly of lounging and drinking around a pool, though one video posted last year does contain some nudity, where women can be seen exposing their breasts. The page appeared to have been taken down on Monday afternoon.

Siem Reap court spokesman Yin Srang did not comment on the case, only pointing to court documents, and anti-human trafficking and provincial police officials declined to comment.

A relative of one of the detainees, who asked to remain anonymous, said on Sunday that the police had prevented women dressed in bikinis from putting on their clothes before they were photographed and had demanded bribes from attendees.

Additional Reporting by Ananth Baliga