and in 1943, FRA moved its headquarters to Lovön, some 15 km from Stockholm. In the 1960s, even the location of the FRA headquarters was still highly secret. Notable events Operation Stella Polaris In the final stage of the Continuation War, 1943–44, when the Soviet Union threatened to occupy Finland, Finnish intelligence requested to transfer about 200 specialists and advanced intelligence equipment to Sweden to establish an exile organisation. A transfer of a small contingent personnel and materials, Operation Stella Polaris, was carried out over a couple of nights in September 1944. Stella Polaris gave Sweden access to a wealth of qualified materials and signals intelligence officers, some of which were also employed. For Finland, it resulted in a domestic political affair and due to the Communist Party's strong influence in the government, several of the so-called "Soviet Hostiles" involved received prison sentences. The Catalina affair On 13 June 1952, the Swedish Air Force aircraft Tp 79 Hugin (DC-3) disappeared during a signal intelligence reconnaissance mission east of the Swedish island of Gotland in the Baltic Sea. The Swedish government initially claimed that the flight was only a navigational exercise, but later admitted that the aeroplane had U.S. electronic surveillance equipment and five specialists from FRA on board. Three days later, a Swedish Air Force search-and-rescue plane of the type Tp 47 (Catalina) was shot down by a Soviet MiG-15 fighter, but the crew was rescued by a nearby West German freighter ship. The Soviet Union denied any involvement in the disappearance of the DC-3, despite the fact that a raft from the aeroplane was found during the search with shrapnel from MiG-15 ammunition. In 1956, the Soviet leader Nikita Khrushchev admitted to Swedish Prime Minister Tage Erlander that the Soviet Union was indeed responsible for shooting down the plane, but this was not made public, not even to the relatives of the crewmen. Russia officially acknowledged the shooting down in 1991. In 2003, the wreck of the shot-down DC-3 was found about 55 km east of Gotland. Several of the crewmen's remains were found in the fuselage and the damage to the plane showed that it really had been shot at by a Soviet MiG-15 fighter. Organizational structure FRA's operational activity are organized into four departments: The Signals Intelligence Service (), The Department for Internet Operations (), The Department for Internal Support Services () and The Department for Technical