The Imperial Security Bureau (also known as the ISB) is a law enforcement and intelligence agency featured in the Star Wars franchise.
During the time of the Empire, the ISB was established as a police task force for the galaxy but in truth acted as an enforcer group. They were filled with crept officers and led by Wullf Yularen
Agent Alexsandr Kallus used to be a member of the ISB before defecting to the rebels' side after his life was saved by Garazeb Orrelios.
By the end of the war the ISB was presumably dissolved with the rest of the Galactic Empire when it collapsed during the Battle of Endor thanks to the efforts of Luke Skywalker and the Rebels.