The mainland's anti-graft organisation is building a fearsome reputation as a massive campaign against corruption gains momentum.
The Communist Party's Central Commission for Discipline Inspection (CCDI) has announced investigations into at least 26 senior officials at the provincial and ministerial level since December 2012, with more to follow. But the agency's operation has remained largely a mystery to the outside world. A mainland magazine, China Economic Weekly, recently tried to shed light on its work.
The CCDI's working processes include five steps - accepting a complaint, initial verification, opening the case, investigation, then a transfer to the justice system.
Complaints from members of the public - usually via petitions to the Offices of Letters and Calls, the traditional bureaus that handle grievances - are the main way for the CCDI to locate corrupt officials.
In September, the CCDI set up a special area on its website to encourage people to file complaints. In the past eight months, the website has received more than 74,000 complaints, more than twice the number before the service was launched. Just over 40 per cent of all investigations since 2012 were triggered by complaints from citizens, the CCDI said, making the public the most important source of information for anti-graft officials.
Businessmen were likely to confess and name to investigators the officials they had bribed, the magazine quoted a senior anti-graft official as saying.
"Officials must not accept bribes from businessmen as they are very likely to confess this to investigators," the agent said.
Colleagues, friends or corrupt officials' lovers normally discussed the misbehaviour of corrupt officials after a certain period of detention, the official said.
Once a tip-off is deemed credible, CCDI officers will try to verify the claim before reporting to their superiors. Investigations of very senior officials, such as members of the Politburo, normally require the approval of the Politburo Standing Committee.
The decisions to investigate the former party chiefs of Shanghai and Chongqing , Chen Liangyu and Bo Xilai - who were among the 25 members of the Politburo - were taken by the smaller, more senior Politburo Standing Committee, the party's highest decision-making body.
Chen was sacked in 2006 and jailed for 18 years in 2008 for taking 2.4 million yuan in bribes and for abuse of power. Bo was sentenced to life imprisonment last year for similar crimes.
The CCDI earlier this year expanded its offices from eight to 12, significantly boosting its manpower. Chen Wenqing, deputy head of the CCDI, said each branch office had 30 inspectors, for a total of 360 inspectors.
The CCDI has also instructed its officers to handle the cases more quickly.
"Previously, some complex cases might last two to three years. But now the investigation process has sped up and the basic requirement is to finish the cases as soon as possible," the magazine quoted a local CCDI official as saying.
"Some cases were conducted directly by the CCDI, even without informing the provincial government. The CCDI would only tell them that the suspected corrupt officials had been detained."
With the boosting of its power, the CCDI also established an internal supervision office in March. At least two senior officials with the agency were put under investigation in May, including Cao Lixin and Wei Jian.
Investigated officials are always put under shuanggui, a secretive and controversial extra-judicial disciplinary measure that the party imposes on its own members suspected of corruption.
The experience for interrogated party members can be as brutal as it is efficient - detainees are subjected to extreme mental and physical pressure - and most corrupt officials confess eventually.
According to the report, extra steps are put in place to prevent detainees committing suicide. For example, suspects are usually put in rooms no higher than the first floor. Electrical cables are concealed behind walls and toilet doors cannot be locked from inside.
Officials found guilty of corruption are normally sacked from their jobs and expelled from the party, before they face any judicial proceedings.