After a detention and trial period of 450 days, the Phnom Penh Municipal Court yesterday sentenced opposition Senator Hong Sok Hour to seven years in prison for displaying a “fake” border treaty between Cambodia and Vietnam on Facebook.

The Sam Rainsy Party senator, who was seized by armed police two days after Prime Minister Hun Sen called for his arrest for “treason” in August 2015, was convicted of forging public documents, using forged public documents and incitement to commit a crime.

Giving little in the way of explanation, judge Ros Piseth yesterday read out the sentence to an empty dock, with Sok Hour and his lawyers choosing not to attend the hearing.

“After listening to the conclusion of the prosecutor, the conclusion of the lawyers, and the final words of the accused, and after considering thoroughly based on the facts and the law, the court decides to sentence Hong Sok Hour to seven years,” Piseth said, before detailing the charges.

Reached after the hearing, defence lawyer Choung Choungy said his team skipped the hearing because he considered the ruling a foregone conclusion, adding he had yet to discuss with his client whether to lodge an appeal.

The accusations against the senator, who was arrested despite his senatorial immunity, stem from documents he presented as a 1979 treaty between Cambodia and Vietnam in a video clip posted on the Facebook page of Cambodia National Rescue Party president Sam Rainsy, who has been charged as an accomplice in the case, as have at least two opposition social media workers.

The controversy surrounded Article 4 of the purported treaty discussed by Sok Hour, in which then-Cambodian head of state Heng Samrin appeared to agree to dissolve the two countries’ borders. During the trial, Sok Hour, a dual French-Cambodian citizen, said he had found the documents online rather than forged them and didn’t know they were fakes.

Via email yesterday, Rainsy, who fled abroad last year to avoid arrest in a separate case, said the version of the treaty used by Sok Hour was more likely a mistranslation than a doctored fake, with the word “dissolve” replacing the word “redefine”.

In any case, he said there was ample evidence that the documents were not created by the senator and had circulated online for years.

“Seven months before the June 2017 commune election this verdict is another act of political repression in order for Hun Sen’s CPP to pervert the election process by creating and maintain an atmosphere of fear and intimidation,” Rainsy said.

Senior CNRP lawmaker Son Chhay, among the few opposition figures to attend yesterday’s hearing, said the heavy sentence, though not surprising, was a sign relations between the CNRP and ruling Cambodian People’s Party were far from improving.

“The court is also only to serve politics . . . and the verdict today makes it difficult to see where the situation will go next,” said Chhay, before adding the party would continue to push for a deal.

With more than 20 opposition and human rights figures in prison, human rights groups slammed yesterday’s verdict as the continuation of efforts by the CPP to crush its opponents.

Chak Sopheap, executive director of the Cambodian Center for Human Rights, called the trend “extremely alarming” ahead of elections in 2017 and 2018, while labelling Sok Hour’s case “unconstitutional” and “politically motivated”.

Asia director for Human Rights Watch Phil Robertson agreed. “This is another example of a politically trumped up charge used to throw an opposition party member behind bars for an incredibly long time,” Robertson said.

“He should be released immediately; he’s done nothing wrong. When are these travesties of justice going to stop?”