The Supreme Court on Wednesday upheld a verdict sentencing former CNRP leader Sam Rainsy to one year and eight months in jail for claiming that the “state” was responsible for the assassination of revered political analyst Kem Ley in 2016.

After Ley was shot dead at a Caltex gas station in Phnom Penh – days after criticising Prime Minister Hun Sen’s family in a radio interview – Rainsy took to Facebook to describe the murder as an act of "state-sponsored terrorism". The gunman, Oeut Ang, was convicted last year but his professed motives have been questioned by his own family, and even authorities have acknowledged that he likely did not act alone. Nonetheless, the investigation into the killing was closed with no further arrests.

The Supreme Court hearing on Wednesday morning lasted less than an hour. Presiding Judge Kim Sathavy announced that the Supreme Court "agreed with the decision made by the municipal court and Appeal Court on the facts of the matter". A fine of 10 million riel fine (about $2,500) also was upheld.

Rainsy was convicted of defamation and incitement to cause chaos in society by the Phnom Penh court in March 2017. He has been in self-imposed exile since 2015 to avoid a slew of convictions.

Ky Tech, the lawyer for Prime Minister Hun Sen, said footage of the shooting proved that Ang was the killer, and that Rainsy’s “claim affected the dignity of Samdech Techo Prime Minister”.

Tech added that Rainsy later repeated the accusation on RFA “to make the people not trust Prime Minister and stop voting for his party”.

Rainsy's defence lawyer Sam Sokong was not present for the hearing but said in a letter that Rainsy was not accusing any specific group or individual of Ley’s murder, and was simply asking the government to look for others who may have been linked to the killing.

However, in an email on Wednesday, Rainsy maintained his belief that Ley was killed by authorities and added that “millions of Cambodians as well as countless independent observers share my belief”.

Additional reporting by Andrew Nachemson