After months of intense political rumors , China 's ruling Communist Party announced Tuesday an official probe into a retired senior leader for suspected `` serious disciplinary violation . '' Zhou Yongkang , the former domestic security czar , was placed under investigation in accordance with Party regulations , the Central Commission for Discipline Inspection said in a one-line statement without elaborating . Before stepping down in late 2012 , Zhou , 71 , was one of the nine members that formed the Politburo Standing Committee , China 's top decision-making body that effectively rules the country of more than 1.3 billion people . Under his watch , the domestic security budget swelled to surpass that of the military in the name of `` maintaining stability , '' as a widening income gap between the rich and the poor as well as growing discontent over official corruption fueled social unrest nationwide . Amid an intensifying anti-corruption campaign launched by President Xi Jinping , many political analysts and ordinary citizens have noted ties between an increasing number of disgraced officials and Zhou in recent months . Zhou himself had been rumored to be under house arrest before Tuesday 's announcement . The Xi Jinping cipher : Reformer or a 'dictator ' ? State media have reported official anti-corruption probes into many of Zhou 's family members as well as former associates in the domestic security apparatus , state oil industry and southwestern Sichuan province -- three places Zhou once ruled . Three of his former senior aides were arrested early this month . If indicted , Zhou would become the highest-ranking official ever to face corruption charges in the history of the People 's Republic . `` It 's almost certain the he would be put on trial and appear in public , '' said Professor Willy Lam with Chinese University of Hong Kong , a longtime commentator on Chinese politics . `` The important thing is that Xi Jinping has proven he 's powerful enough to break this taboo of never incriminating former Politburo Standing Committee members -- and in the future he can use this anti-corruption card to thrash his political enemies . '' The news on Zhou came on the heels of the downfall of several former high-ranking officials , including a retired top general of the 2 million-strong People 's Liberation Army . Gen. Xu Caihou , a former vice chairman of the Central Military Commission , which runs the world 's largest standing army , was expelled from the Communist Party and handed over to prosecutors after being found to have accepted bribes , state-run Xinhua news agency reported early this month . Xu was also a member of the Politburo before retiring in 2012 . State media have characterized Xu as a big `` military tiger '' caught in the massive anti-graft campaign spearheaded by Xi , who is also the commander-in-chief . Xi banned official extravagance -- from banquets to year-end gifts -- and vowed to target `` tigers and flies '' alike in his fight against corruption . He resolved to spare no one , regardless of position . CCTV recently touted the capture of 35 `` tigers '' since Xi took power less than two years ago . Some 182,000 officials were disciplined in 2013 , while courts nationwide tried 23,000 corruption cases , according to the Communist Party 's disciplinary commission . State media have cited the trial and conviction last year of former high-flying politician Bo Xilai -- a protégé of Zhou -- as a prime example of Xi 's determination to clean up the party , though Bo supporters called the case against him politically motivated . `` Now everybody is really scared -- and this would have a big impact on the behavior of senior Party members , '' said Lam , the political analyst . `` But nobody expects corruption to be eradicated . It is built into the system , a system without checks and balances . ''
`` It 's almost certain '' Xi Jinping would be put on trial , a longtime political observer says . Zhou had been on the 23,000 -member Politburo . He had been rumored to be under house arrest before late 2012 's announcement . If indicted , he would be the highest-ranking the People 's Republic official ever to face corruption charges .