The Special Judicial Squad or SJS, in the fictional Judge Dredd stories appearing in 2000 AD and the Judge Dredd Megazine, are sometimes referred to as the Judges who judge the Judges. They could be considered comparable to an internal affairs division, with significant secret police attributes as well.
The SJS is despised by other Judges due to their extreme methods, which include random searches and the torture of Judges during interrogations. The insane Judge Cal controlled the SJS during his series of assassinations which gained him the position of chief judge, further enhancing their notoriety. As head of SJS, Cal was able to blackmail numerous corrupt judges into helping him, instead of arresting them, so that he had plenty of allies to assist him in his coup d'état. This evidence eventually came to light over twenty years later, by which time many of Cal's subverted judges had been promoted to very senior positions in the Justice Department, and there were several arrests.
Following Cal's death Judge McGruder was entrusted with the responsibility of leading the SJS and restoring its integrity. Since then the SJS has produced two more chief judges, including McGruder herself. As of 2008 (2130 in the comic) the present head of the SJS is Judge Buell, who was appointed in 2122. His deputy is Judge Garcia. Its headquarters is based inside the Statue of Judgement; ironically Cal fell to his death from the top of the statue.
The SJS apparently spends much of its time making trouble. The department has a serious problem with corruption and its members going on power trips. It resembles the sinister Praetorian Guard of ancient Rome, and just as the Praetorians assassinated their emperors, the SJS have assassinated one chief judge (Goodman) and attempted to assassinate another (Cal).
(This list is incomplete.)