Wall Street JournalEx-China security chief under investigationCNN(CNN) -- Zhou Yongkang, China's retired chief of domestic security, is under investigation because of "suspected severe disciplinary violations," the ruling Communist Party of China said Tuesday. There had been a string of purges of former aides to Zhou, ...China: Ex-security czar Zhou under investigationWashington PostChina investigates ex-security chiefBBC NewsCPC confirms Zhou Yongkang placed under investigationWantChinaTimesall 22 news articles »