War came to eastern Poland with the Soviet invasion of 17 September 1939. Czarkowski-Golejewski was arrested on his estate at by officers of the Soviet security service on 21 September 1939. His younger brother had already been arrested four days earlier. He was one of those detained in the camp at Kozelsk. There remains a lack of precision over the dating of the massacres grouped together in sources and defined collectively as the Katyn massacre, but the operation is believed to have been approved by the Soviet party politburo in March 1940. Of those killed, approximartely 8,000 were officers imprisoned during the 1939 Soviet invasion of Poland, another 6,000 were police officers, and the remaining 8,000 were Polish intelligentsia the Soviets deemed to be "intelligence agents, gendarmes, landowners, saboteurs, factory owners, lawyers, officials, and priests". Cyryl Czarkowski-Golejewski and his younger brother were among those killed. Their names are among the 3,435 included on the so-called Ukrainian Katyn List dated 25 November 1940 and forwarded to Poland's then deputy Prosecutor General, , by General Andrija Chomicza, a senior member of the Ukraine security service, on 5 May 1994. Physical remains of Katyn massacre victims are believed to be among those buried at the unmarked mass grave site known as the Bykivnia graves, a short distance from the centre of Kyiv."