Nelson received special training at the [[Lenin School]] in [[Moscow]] in 1931, and in 1933 acted as an operative for the [[Communist International]] in [[Shanghai]], China. In 1936 and 1937, he served as a lieutenant colonel in the Communist-recruited [[International Brigades]] in Spain. Although active as a Communist Party organizer in California and Pennsylvania and as a member of the Communist Party National Committee, his most important assignment was [[atomic espionage]]. | Nelson received special training at the [[Lenin School]] in [[Moscow]] in 1931, and in 1933 acted as an operative for the [[Communist International]] in [[Shanghai]], China. In 1936 and 1937, he served as a lieutenant colonel in the Communist-recruited [[International Brigades]] in Spain. Although active as a Communist Party organizer in California and Pennsylvania and as a member of the Communist Party National Committee, his most important assignment was [[atomic espionage]]. |