A Beijing court has sentenced a U.S. geologist to eight years in jail on state secret charges on Monday.

A naturalized U.S. citizen, Xue Feng received the sentence more than two-and-a-half years after he was detained in November 2007.

According to rights group Dui Hua Foundation, Chinese security agents detained Xue because he purchased and sold a database about China’s oil industry.

Xue and his employer at the time, American energy consulting firm IHS Energy, say the database was a commercially available product. But after Xue purchased the database, the Chinese regime classified it as a state secret.

Xue says under detention security agents tortured him and burned him with cigarettes, leaving scars on his arms.

U.S. Ambassador to China Jon Huntsman attended the sentence hearing. He’s calling on Chinese authorities to release and deport Xue back to the United States immediately.

Xue Feng’s case highlights concerns by foreign businesses over the Chinese regime’s use of vague state-secrets laws to restrict business information.