0th Investigation Department

The 0th Investigation Department is a rumored special investigative division of the Japanese police that specializes in dealing with spiritual matters. It is unknown if the organization actually exists in the Toaru Majutsu no Index universe.

Angel Fall Arc
Kanzaki Kaori references the department after Tsuchimikado Motoharu says that the police force, that was tasked on guarding the residential area where Touma's house (which has been invaded by Hino Jinsaku) lies, has forced the media to move away which makes Touma and Motoharu's job much simpler.