Three people have been detained for exploiting mentally challenged workers in Quxian county, Southwest China's Sichuan province, and six officials involved in the case were held accountable, the local official news website reported Wednesday.

A farmer and once an executive committee member of Quxian Federation of Industry and Commerce, Zeng Lingquan, and his wife have been taking in mentally challenged people and selling them to workplaces since 1993.

In a recent case, they sent a number of workers to a building materials factory in the Xinjiang Uygur autonomous region, and received salaries supposed to be paid to the workers.

In 2006, the couple signed a contract with Yang Junyi, a worker in a local rehab center, and sold the latter three workers.

Police detained the couple and Yang in mid-December. Quxian government decided on Dec 30 to dismiss four officials involved in the case, including the head of the rehab center and the head of the county civil affairs bureau. Two other officials were admonished.