Born Samnang and Sok Sam Oeun have now been imprisoned for nearly five years since their arrests for the murder of Chea Vichea in January 2004.

Amnesty International calls on Cambodian's highest court to overturn their convictions:

"The Cambodian Supreme Court must dismiss the case against both men and ensure that they are released." said Amnesty International's Cambodia researcher Brittis Edman.

Amnesty International has repeated its calls to the Cambodian authorities to conduct an impartial and effective investigation into the murder of Chea Vichea so that those responsible for it are brought to justice.

The organisation has also urged the authorities to initiate a thorough, independent and impartial investigation into the conduct of the case - including allegations of torture or other ill-treatment by police during the initial interrogation of the two men, intimidation of witnesses and political interference with the judicial process.

The Supreme Court is to hear the case on Dec 31.