In late 1943, Fuchs (codename: "Rest"; he became "Charles" in May 1944) transferred along with Peierls to Columbia University, in New York City, to work on gaseous diffusion as a means of uranium enrichment for the Manhattan Project. Although Fuchs was "an asset" of GRU in Britain, his "control" was transferred to the NKGB (Russian: Народный Kомиссариат Государственной Безопасности), the Soviet Union's civilian intelligence organisation, when he moved to New York. He spent Christmas 1943 with Kristel and her family in Cambridge. He was contacted by Harry Gold (codename: "Raymond"), an NKGB agent in early 1944.
In late 1943, Fuchs (codename "Rest"; he became "Charles" in May 1944) transferred along with Peierls to Columbia University, in New York City, to work on gaseous diffusion as a means of uranium enrichment for the Manhattan Project Although Fuchs was "an asset" of GRU in Britain his "control" was transferred to the NKGB (Russian: Народный Kомиссариат Государственной Безопасности), the Soviet Union's civilian intelligence organisation, when he moved to New York. He spent Christmas 1943 with Kristel and her family in Cambridge. He was contacted by Harry Gold (codename: "Raymond"), an NKGB agent in early 1944.