The ISB headquarters office was the headquarters of the Imperial Security Bureau in the city of Selkren during the Galactic Civil War, until the city was destroyed along with the rest of the planet Demophon when its sun went supernova.
The ISB headquarters office was a cylindrical building of modular prefabricated design comprised of nine stories and two sub-levels. Chutes used for waste disposal connected sublevel two and the municipal sewer system. Several secret entrances were maintained on sublevel one, allowing ISB agents to enter and exit covertly.
- Ground Floor contained the entrance, the ISB motorpool, and a preliminary interrogation room.
- Level 2 housed the Surveillance branch.
- Level 3 housed the Investigation branch.
- Level 4 housed the Internal Affairs branch.
- Level 5 housed the Interrogation branch.
- Level 6 housed the Re-Education branch.
- Level 7 housed the Enforcement branch.
- Level 8 housed the command, communications, and medical centers.
- Level 9 housed the flight support deck.
- The roof was modified to support landing for small starships.
- Sublevel One contained the detention block and interrogation rooms.
- Sublevel Two contained the primary and auxiliary reactors, life support, and facilities for support technicians.
During the Galactic Civil War the sun of the Demophon system was found to be approaching supernova. Most of the ISB personnel evacuated, but Captain Wallace Fisk led a team which remained behind to evacuate the prisoners, transfer the ISB data to portable computer banks, then wipe the ISB files. As he was doing so the building came under attack by a team seeking to rescue Thadius Black and his associates.