China's Ministry of Supervision stated on its website on Feb. 18 that the deputy governor of the southern province of Hainan, Ji Wenlin, is under investigation for serious violation of discipline, a byword for corruption.

Sources also told Shanghai's China Business News that Shen Dingcheng, Communist Party chief of the international business division of state oil company China National Petroleum Corporation (CNPC) was incommunicado, indicating that he may likewise be under investigation. CNPC has not commented on the matter.

The paper reported that at least ten senior officials from the state-run CNPC have been placed under investigation or cannot be contaced.

Shen and three other senior figures — former CNPC general manager Li Hualin, former chairman of Sichuan's art association Guo Yongxiang and former Hainan deputy governor Ji Wenlin — had previously served as a secretary to a retired executive at CNPC.

Shen had served as vice president of CNPC's international business division and at a CNPC subsidiary before being promoted to the post of party chief in 2007 and assuming one of the leading roles at the company.

Between 1992 and 1997, he was secretary at CNPC headquarters. Sources said Shen took over the position from predecessor Li Hualin as secretary of an executive at CNPC.

In 1998, Shen was transferred to vice president of a CNPC subsidiary and Ji continued Shen's work as secretary.

Ji held the post for a decade till December 2008, when he returned to the Ministry of Land and Resources. He was made mayor of the Hainan provincial capital Haikou in February 2011 and became the youngest deputy governor of Hainan in 2013 at age 47.

Ji was last seen in public as deputy governor on Feb. 14 this year.