Born Samnang, center, and Sok Sam Oeun, right, surrounded by relatives exit a courthouse following their appeal hearing, Friday, Oct. 6, 2006, in the capital Phnom Penh, Cambodia.

Sam Rainsy party (SRP) Tuesday demands the release of the two men wrongly convicted for killing Chea Vichea, former leader of Free Trade Union of Workers of the Kingdom of Cambodia.

On January 2006 (Chinese New Year), Vichea was shot in the head and chest early in the morning while reading a newspaper at a kiosk in Daun Penh district, Phnom Penh.

Sok Sam Oeun and Born Samnang were judged guilty after a trial where no witnesses came to testify against the accused and no forensic evidence was brought to court. Both individuals were sentenced to 20 years in prison and ordered to pay $5,000 compensation each to the family of the victim.

On Tuesday, Cambodian opposition party issued a statement supporting a pro-democracy group’s campaign to free Sok Sam Oeun and Born Samnang from prison. SRP officials believe that the real killers are still at large and claimed that these two men are wrongly convicted.

Chea Vichea, former president of FTUWKC

While, Ministry of Interior's spokesman, Khieu Sopheak cannot be reached for comment, Deputy Prime Minister Sar Kheng's adviser Chuon Mom Thol, considers SRP’s demand to be politically motivated.

Many people including, former King Norodom Sihanouk do not believe that the two men are guilty. Human Rights Watch Asia and Amnesty International issued a statement last year, urging the Cambodian government to release them.

As such, Cambodia Human Rights Action Committee (CHRAC), a coalition consists of 21 non-governmental organizations have set up billboards campaign for their release, last Sunday.

Vichea’s younger brother, Chea Mony tells VOA Khmer that should they be released from prison, Cambodia is one step closer to redeem its tainted image.

After the two men were charged, Phnom Penh court received highly criticizes judgment by both local and international organizations- calling it unfair and politically biased.