Human rights groups have called for the release of two men in Cambodia ahead of their appeal against convictions for murdering a prominent union leader.
The anniversary of their trial was marked with a special ceremony
Rights groups say Born Samnang and Sok Sam Oeun were framed for the killing of Chea Vichea, in January 2004.
They point to numerous police and judicial irregularities and say a key witness has submitted a new statement saying the men were not the killers.
Chea Vichea was shot dead at a news stand in the capital Phnom Penh.
He was president of Cambodia's Free Trade Union of Workers (FTUWKC), one of the country's most active unions, with about 30,000 members.
He was an outspoken critic of government corruption and human rights abuses.
His union said at the time the killing was politically motivated. At least three other members of the opposition were also killed around the same time.
After their arrest a week later, Born Samnang confessed to the crime. But he told his trial in August 2005 that the confession had been obtained under torture.
"These men are scapegoats who never should have been arrested, much less imprisoned for three years already," Brad Adams, of Human Rights Watch (HRW), said.
Chea Vichea was one of Cambodia's best-known campaigners
Both Chea Vichea's family and the former King Norodom Sihanouk have proclaimed the men's innocence. As well as HRW, their case also has the support of Amnesty International and the International Confederation of Free Trade Unions.
The appeal on Friday will hear a statement from the former owner of the news stand, Va Sothy.
In her first signed statement, written after fleeing to Thailand because she said she feared for her life, Va Sothy says Born Samnang and Sok Sam Oeun are not the men she saw shoot Chea Vichea.
"This new testimony from the prime eyewitness to the murder is the final blow to a prosecution case that was critically flawed from the beginning," Mr Adams said.