Longstanding Cambodian opposition figure Sam Rainsy is in court in France, facing defamation cases brought against him by top officials in his home country.
The 73-year-old was targeted with two separate complaints by Cambodian Prime Minister Hun Sen and his son-in-law and deputy national police chief, Dy Vichea, over Facebook posts from 2019.
Rainsy claimed that Hun Sen was behind the 2008 death in a helicopter crash of national police chief Hok Lundy, the father of Dy Vichea's father.
"Hun Sun killed Hok Lundy using a bomb placed inside his helicopter," Rainsy said on Facebook.
The leader of Cambodia's government "decided to murder Hok Lundy because he knew too much about Hun Sen's misdeeds", he added.
Hun Sen contests Rainsy's claim, and Dy Vichea has brought a second complaint over a separate 2019 Facebook post.
The judges could take several weeks to deliver a verdict after Thursday's hearing.
Luc Brussolet, a lawyer representing both Cambodian officials, said he expected the court to "find the remarks in question defamatory".
But Rainsy's lawyer Jessica Finelle told AFP that judges ought to "recognise that it is in the public interest for Sam Rainsy to denounce crimes committed by Hun Sen within a dictatorship".
Main opposition movement
Rainsy "has been persecuted for 30 years by Hun Sen. The only weapon remaining to him is freedom of expression, to testify about what he has experienced and condemn what political opponents and human rights defenders are suffering in Cambodia", Finelle said.
Rainsy was one of the founders of the Cambodia National Rescue Party, the country's main opposition movement and he spent years opposing Hun Sen, who has ruled the country for the past 37 years.
Rainsy went into exile in in 2015 in France, where he is a dual national.
He is the target of many court cases in Cambodia, where he says he is being persecuted for political reasons.
The government there accused him of an attempted coup when he sought to return in 2019.
"In his home country, Sam Rainsy is the victim of a slew of trials, the regime is trying to muzzle him," said another of his lawyers, Mathias Chichportich.
The French tribunal should "enshrine Sam Rainsy's right to express his political struggle" and "exonerate him", he added.
"His words are founded on a solid factual basis."
Although Rainsy's party performed strongly in the 2013 elections, it was dissolved four years later.
In 2018, Hun Sen's movement swept every seat in Cambodia's parliament, a result that was fiercely contested.
Since then, increasing numbers of dissidents have been arrested and prosecuted.
Dozens of opposition figures were sentenced in a mass trial in June, with Rainsy receiving an eight-year prison sentence in his absence.
He has already been sentenced to jail terms of 10 and 25 years in absentia for trying to topple Hun Sen, who is expected to run again in elections next July.