A billionaire Chinese petrochemical entrepreneur on Monday became the fifth senior industry figure in a week to become enmeshed in a corruption investigation that continues to reach higher into China's political and economic elite.
The entrepreneur, Hua Bangsong, 47, is "now assisting the relevant authorities in the P.R.C. in their investigations," according to a filing made late Monday to the Hong Kong Stock Exchange by Mr. Hua's company, Wison Engineering Services.
(Read more: China expands inquiry on graft to oil industry)
A crackdown on corruption in China has intensified in recent weeks, focusing on the oil industry. Mr. Hua's company is one of the largest nonstate contractors to the oil and gas industry in China, and counts the China National Petroleum, or C.N.P.C., as one of its biggest customers.
Last week, four senior managers of C.N.P.C. and its subsidiary, PetroChina, were removed from their positions and placed under investigation on suspicion of what an official statement called "grave violations of discipline," almost always a reference to corruption, bribe-taking or embezzlement.