China is investigating a former senior executive of China National Offshore Oil Company, or CNOOC, for suspected "serious disciplinary violations", the country's anti-graft watchdog said on its website late on Monday. The Central Commission for Discipline Inspection (CCDI) said in a brief statement the executive was Qi Meisheng, ex-chairman of the state energy group's gas and power unit. Qi was also a deputy chief economist at CNOOC.