Rights groups and the United Nations yesterday urged the Supreme Court to drop the case against two men widely believed to have been wrongfully convicted of the slaying of unionist Chea Vichea when it convenes this morning.

Born Samnang and Sok Sam Oeun were re-arrested in December of last year after spending nearly four years out of prison on provisional release after the Appeal Court issued a shock verdict finding the pair guilty of the 2004 murder.

“Prosecutors have long conceded that there was no basis for convicting the two men prosecuted for Chea Vichea’s murder, yet the government has persisted in this miscarriage of justice,” Brad Adams, Asia director of the US-based Human Rights Watch, said.

“The Supreme Court now has the opportunity to render a measure of justice for the wrongfully convicted Born Samnang and Sok Sam Oeun.”

The men were implicated shortly after the outspoken unionist was gunned down in daylight in January 2004.

Though there was ample evidence to suggest the pair had been framed – a fact later admitted by former municipal police chief Heng Pov – they received 20 years in 2005.

After almost five years in prison, Samnang and Sam Oeun were provisionally released in January 2009 by the Supreme Court, which ordered a re-investigation. But, after years of the case bouncing between the upper and lower courts, when the Appeal Court re-tried the pair in December 2012, it found them guilty and remanded them to custody.

Amnesty International yesterday characterised the original trial as “grossly unfair” and urged “both men to be released immediately and unconditionally”, while the UN OHCHR and International Labour Organization highlighted a “lack of sufficient evidence to prove guilt”.

Neang Khen, the wife of Sam Oeun, said she and her two-year-old daughter had struggled with poverty since her husband’s re-arrest.

“Everyone including the King knows that my husband and Born Samnang are artificial murderers, so please may the court tomorrow release them,” Khen said.