Suspected ghostwriters are investigated by the plainclothes policemen in Jinan, capital of Shandong province, June 5, 2014. [Photo/CFP]

ZHENGZHOU -- Six candidates in Central China's Henan Province for the national college entrance examination, or "gaokao," have been punished for organizing substitutes to sit the exam in their place, local education authorities said on Tuesday.

The Provincial Higher Education Admission Office said that the test results of six students from high schools in Qixian and Tongxu counties have been canceled, and they will be barred from participating in any national examinations for the next three years.

Their parents and the invigilators are under police investigation, the office said.

Authorities are continuing to investigate the case, and will keep looking for others who cheated during the gaokao.

The scandal, exposed on June 17, sparked fresh concerns about flaws in the exam, which involved more than nine million students on June 7 and 8.