Nahum Isaakovich Eitingon ( Naum Isaakovič Ejtingon), also known as Leonid Aleksandrovich Eitingon () (6 December 1899 – 3 May 1981), was a Soviet intelligence officer, who gained prominence through his involvement in several NKVD operations, including the assassination of Leon Trotsky, the orchestration of partisan movements during World War II, and atomic espionage. He has been described by Yevgeny Kiselyov as one of the organisers and managers of the state terrorism system under Joseph Stalin and later a victim thereof. He was the great-cousin of Max Eitingon. Early life Eitingon was born into a Lithuanian Jewish family in Shklow, Belarus, then part of the Russian Empire. His father, Isaac Faivelovich Eitingon, was a paper mill clerk, and his grandfather was a lawyer. Shortly before the Russian Revolution his family moved to Mogilev, where Nahum studied at Mogilev Commercial School. Eitingon first became involved in labor during the German occupation of Mogilev, when he joined a cement worker's union and joined the Left Socialist-Revolutionaries. In his memoirs, KGB General and friend and colleague of Eitingon Pavel Sudoplatov claimed that Eitingon had fought in the Red Army since 1918, however, this claim is not substantiated by official records of the time. Following the Russian Revolution, he became a clerk at the commodities exchange. Following several promotions within the local labor bureaucracy, he joined the CPSU in 1919. Intelligence career Eitingon joined the Cheka on May 10, 1920, having been recruited to a shortage of Chekists in the area. Along with other Chekists, he took part in numerous operations during the Russian civil war, including the "liquidation" of a number of the more prosperous citizens of the Belarusian town of Gomel. He also gained prominence at the time for his work against banditry in Belarus. Eitingon was temporarily ejected from the Cheka and investigated during a 1921 purge due to his bourgeois origins, however, he was quickly let back in. In 1924, he graduated from Frunze Military Academy, after which served at several diplomatic postings in China and Turkey under the auspices of the OGPU. From 1927–1929 he served as Vice-Consul General at the Consulate of the USSR at Harbin. He also served at the special operations directorate of the OGPU from 1930–1932 and served under Alexander Orlov during the Spanish Civil War, using his linguistic skills to adopt several aliases. During this time, he was involved in several operations, including the