China has begun an investigation into former domestic security chief Zhou Yongkang, one of the most powerful politicians of the last decade, on suspicion of corruption, state media said on Tuesday, in what could be one of the country's worst scandals.
The ruling Communist Party has decided to probe Zhou for suspected "serious disciplinary violations", the official Xinhua news agency said in a brief dispatch, using the usual euphemism for corruption.
The investigation will be conducted by the party's graft watchdog, the Central Commission for Discipline Inspection, and the decision was made in line with the party's constitution and anti-corruption regulations, Xinhua added, without giving details.
Zhou, 71, is the most senior Chinese politician to be ensnared in a graft scandal since the Communist Party swept to power in 1949.
Reuters reported in early December that Zhou had been placed under virtual house arrest while the party investigated corruption accusations against him.
Zhou was a member of the party's Politburo Standing Committee - China's apex of power - and held the immensely powerful post of security tsar until he retired in 2012.
During his five-year tenure as security chief, Zhou oversaw the police force, civilian intelligence apparatus, paramilitary police, judges and prosecutors. Government spending on domestic security exceeded the defense budget.
But Zhou became too powerful and that position was downgraded during a sweeping leadership reshuffle in 2012.
Zhou was implicated in rumors in 2012 that he hesitated in moving against one-time contender for top leadership Bo Xilai, who fell in a divisive scandal following accusations his wife murdered a British businessman.
President Xi Jinping has made fighting deeply-engrained graft a central theme of his new administration, and has promised to take down "tigers" - or senior officials - as well as those of lower rank who are implicated in corruption.
In ordering the investigation, Xi has broken with an unwritten understanding that members of the Standing Committee will not be investigated after retirement.
Zhou could not be reached for comment. It is not clear if he has a lawyer.