A Vietnamese court on Friday sentenced Facebook user Bui Van Thuan to eight years in prison–under vague rules that are often used by authorities to stifle criticism–for a series of posts in which he criticized the power struggle among local officials, whom he nicknamed “the dog fighting ring.”

In his final statement during the trial, Thuan, 41, gave up his right to appeal because he said he cannot trust the judicial system in Vietnam.

“The sentence for my husband may have met the authorities’ expectations, but it is utterly unconvincing to me,” his wife, Trinh Thi Nhung, told Radio Free Asia in a text message.

“My husband did not appeal, not because he pleaded guilty or surrendered,” she wrote. “The reason is: No political prisoners have appealed successfully so far.”

The People’s Court in the northern province of Than Hoa found Thuan guilty of “disseminating anti-state materials,” under Article 117 of Vietnam’s penal code. In addition to the time in prison, Thuan must also serve five years probation.

According to the indictment, Thuan penned 27 Facebook posts with “content against the government of the Socialist Republic of Vietnam.”

The prosecution called 12 witnesses but only one, Le Quoc Quyen, who is a Facebook friend of Thuan and the head of Thuan’s local police station, showed up to the court.

According to the defense, the witness could not provide concrete details about the charges against Thuan. But when they requested that criminal charges be brought against the witness for false testimony, the judge denied the request.

“Sending a man to prison for eight years on the basis of a few Facebook posts indicates the government's total intolerance for any sort of criticism,” Phil Robertson, Human Rights Watch’s Deputy Asia Director, told RFA via text message.

“At this point, one wonders why the Vietnam government even bothers to send such cases to trial since the long sentences issued by these kangaroo courts are entirely predictable, and justice and rule of law in the country is a farce,” Robertson said.

According to RFA Vietnamese, Bui Van Thuan is the eighth activist sentenced on charges of conducting propaganda against the state this year. The rest were sentenced to five to eight years in prison and three to five years on probation.