left, both to strengthen advocacy of pro-Soviet policy and to enlarge the pool of potential recruits for espionage work. The illegal residency of NKVD in the US was established in 1934 by the former Berlin resident Boris Bazarov. In 1935, NKVD agent Iskhak Akhmerov entered the US with false identity papers to assist Bazarov in the collection of useful intelligence, and operated without interruption until 1939, when he left the US. Akhmerov's wife, an American who worked for Soviet intelligence, was Helen Lowry (Elza Akhmerova), the niece of CPUSA General Secretary Earl Browder. Recent information from Soviet archives has revealed that Browder's younger sister Marguerite worked until 1938 as an NKVD operative in Europe. She discontinued this work only when Browder himself requested her release from duty, fearful that her work would compromise his position as General Secretary. In the 1930s, the chief Soviet espionage organization operating in the U.S. became the GRU. J. Peters headed the secret apparatus that supplied internal government documents from the Ware group to the GRU. Browder assisted Peters in building a network of operatives in the administration of President Franklin D. Roosevelt. This group included Alger Hiss, John Abt, and Lee Pressman (Pressman admitted participation in the group, but denied it was involved in espionage). Courier for the group at the time was Whittaker Chambers. Browder oversaw the efforts of Jacob Golos and his girlfriend, Elizabeth Bentley, whose network of agents and sources included two key figures at the Department of Treasury, Nathan Gregory Silvermaster and Harry Dexter White. One early Soviet spy ring was headed by Jacob Golos. Jake Golos (birth name Jacob Golosenko, Tasin, Rasin or Raisen) was a Ukrainian-born Bolshevik revolutionary and Soviet secret police (NKVD) operative in the USSR. He was also a longtime senior official of the CPUSA involved in covert work and cooperation with Soviet intelligence agencies. He took over an existing network of agents and intelligence sources from Earl Browder. Golos' controller was the head of the NKVD's American desk, Gaik Ovakimian, also known as "The Puppetmaster", who would later serve a key role in the assassination of Leon Trotsky. Golos was the "main pillar" of the NKVD intelligence network. He had worked with Soviet intelligence from the mid-1930s, and probably earlier. He was not merely a CPUSA official assisting the NKVD (an agent or "probationer" in Soviet intelligence parlance) but held official rank in the NKVD,