The Phnom Penh Appeal Court has upheld a defamation conviction against former opposition leader Sam Rainsy, who had been sentenced to 20 months in prison for claiming Prime Minister Hun Sen’s government was behind the murder of political analyst Kem Ley.

Rainsy’s lawyer, Sam Sokong, said yesterday the court also upheld fines of 10 million riel (about $2,500) to the state and 100 riel (about two and a half cents) to Hun Sen for claiming the murder was an act of “state-sponsored terrorism” – a view held by many Cambodians.

Rainsy, reached yesterday, was defiant.

“I maintain that the Hun Sen government organised Kem Ley’s murder and its subsequent cover-up because nobody else would have been able to commit this act of state terrorism,” he said, noting similar patterns in the high-profile assassinations of monk Sam Bunthoeun in 2003, unionist Chea Vichea in 2004 and environmentalist Chut Wutty in 2012.

He said the verdict was “not surprising” because “the authorities would do anything to prevent the truth about Kem Ley’s death from being exposed”.

Rainsy said he had no faith in Cambodia’s judicial system and instead pinned his hopes on an information-sharing agreement with oil giant Chevron, which owns the Phnom Penh Caltex station where Ley was shot dead on July 10 last year.

Under the agreement the company will this month hand over any files containing search terms like “Hun Sen” and “assassin!” to a California court.