Soble, who now adopted the name Abraham Senin, became publicly known as a prominent member of the German Trotskyist circle, visiting Leon Trotsky himself on at least two occasions. However, suspicions were aroused about his activities and Trotsky booted Senin and his brother from the party. Soble returned to the USSR and began work for Profintern. In 1940, Soviet spymaster Lavrenty Beria dispatched the entire Soble family to the United States, by way of Japan and Canada. Soble later testified that Beria had told him that if he undertook the mission to spy on the United States, Beria would allow Soble's entire family to leave the Soviet Union.