On 26 October 1979, Park was assassinated in a safehouse inside the Blue House presidential complex by Kim Jae-gyu, the director of the Korean Central Intelligence Agency (KCIA) and the president's security chief. Park, four of his bodyguards, and his chauffeur were killed by Kim and other KCIA agents for unknown reasons. The death of Park after 18-years of dictatorial rule caused immediate political turmoil in South Korea. Park was succeeded by Choi Kyu-hah, the Prime Minister since 1975, assuming power as acting president but was almost immediately marginalized by competing factions in the military. After the declaration of martial law following Park's death, General Jeong Seung-hwa acted as the government's chief administrator and appointed Major General Chun Doo-hwan the same day to lead a Joint Investigation Headquarters. On 27 October, Chun unilaterally assumed control of the KCIA and the government intelligence apparatus. On 6 December, the National Council for Unification confirmed Choi Kyu-hah as President according to the framework of the Yusin Constitution, but six days later, Chun spearheaded the coup d'état of December Twelfth, forcibly arresting and detaining General Jeong. By this point Choi had lost any meaningful authority in government, and in early 1980 Chun installed himself as Director of the KCIA.