How China is ruled: Discipline Commission
Party members suspected of corruption, bad management or breaking with the party line are liable to be hauled before discipline inspection commissions, set up to deal with internal party discipline and to monitor abuses.
When ousted leader Bo Xilai's case rocked China in 2012, it was the Central Commission for Discipline Inspection which sealed his fate.
As economic reforms have gathered pace, corruption has become probably the single most damaging issue for the party's standing.
As a result, there have been consistent campaigns to root out corrupt officials and give maximum media coverage to a few, high-profile punishments.
For example, China's railways minister Liu Zhijun was forced to quit in 2011 under investigation for allegedly embezzling more than 800m yuan (£75m; $121m).
More often, powerful party members are able to protect themselves, their families and proteges from any enquiries or public criticism. And because it is the party which investigates the party - it is not prepared to tolerate outsiders monitoring its members' behaviour - the commissions are always prone to interference from higher up.
Discipline inspection commissions do have privileged access to information about people. Their control over networks of informers and personal files makes them particularly feared.