A parent looks for a his lost child at a brick kiln at Liuwu Village in Yuncheng, in China's Shanxi Province June 15, 2007. [AP]

BEIJING - A dozen people went on trial in northern China on Wednesday, charged with murder and illegal detention at brick kilns in a slave labor scandal that shocked the country and exposed the hardships of China's huge migrant work force.

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An official of the Linfen People's Intermediate Court who declined to be identified, confirmed that the trial of the kiln owners, managers and guards in Shanxi province had started.

The 12 defendants include kiln boss Wang Bingbing and foreman Heng Tinghan, Xinhua News Agency said. Heng became the suspected chief villain in the scandal after media said a worker died at the kiln he controlled, and ran pictures of workers with their skin rubbed raw or severely burned.

Heng was captured in central China's Hubei province last month after a nationwide hunt.

Xinhua said he lured 31 rural laborers from railway stations in neighboring Henan, Shaanxi and Shanxi provinces, with offers to help them find jobs. He instead forced them to work in the brick kiln in Hongtong, a county in Shanxi.

The court official would not say what charges the defendants faced. Xinhua said the charges included "illegal detention, forced labor and murder."

The official said no judgment will be made Wednesday and another hearing will be held soon when the court will issue a decision. He gave no further information.

The trial is expected to be the first of many connected to the scandal. Xinhua said 160 suspected kiln bosses have been detained and at least one village-level Communist Party secretary - Wang Dongji, the father of Wang Bingbing - has been expelled from the party.

Investigations have been spearheaded largely by parents searching the mountains of southern Shanxi for missing sons. One group claiming to represent 400 fathers circulated an open letter online saying 1,000 children were being held and accusing officials of ignoring or obstructing their searches.

Since news of the abuse broke last month, more than 8,000 kilns and small coal mines in Shanxi and Henan have been raided, with 600 workers - including more than 50 children - being freed, state media have reported.

Police in Shanxi said 359 people had been freed, Xinhua reported. Premier Wen Jiabao has ordered a thorough probe and punishment of kiln owners and officials who abetted their activities.