Independent radio station owner Mam Sonando was sentenced to 20 years in prison this morning by Phnom Penh Municipal Court on charges related to stoking a so-called secessionist movement in Kratie province.

A second supposed mastermind, Bun Ratha, was sentenced to 30 years in absentia, while three others were given sentences ranging from 10 months to three years.

Over the course of more than three hours, Judge Chang Sinath recounted the charges against the group and the lengthy story behind the separatist movement that Sonando is accused of having masterminded. As she spoke, hundreds of Sonando's supporters gathered outside the court, drawing scores of police.

The Sonando trial has drawn the ire of rights groups, who have called the charges spurious and politically motivated.

Shortly before Sonando's arrest, the premier linked the outspoken government critic with a would-be uprising in Kratie. Claiming they had been cracking down on a secession movement, government officials stormed Broma village in May, killing a 14-year-old girl in the process.

The government’s account has been widely denied by rights groups, who say the raid was merely an excuse to evict hundreds of families locked in a land dispute with agro-business company Casotim.

At court yesterday, Sonando delivered a brief statement saying that despite the verdict, he was "happy" at heart because he knew he was innocent.

Sonando's wife Dinn Phanara, said she would file an appeal. The 70-year-old Sonando has suffered a number of ailments since his July incarceration.

As news of the Sonando verdict reached his supporters outside the court, many found themselves in tears while others seemed stunned.

"I was very shocked that they convicted him. He had so much proof that he was innocent. There's was no proof he did that," said Huon Pannary, secretary-general of Sonando's Association of Democrats, her voice catching as she spoke.

"I was shocked."

To contact the reporter on this story: May Titthara at [email protected]

With assistance from Abby Seiff