Jack Soble

Jack Soble (May 15, 1903 – 1967 ) was a Lithuanian who, together with his brother Robert Soblen, penetrated Leon Trotsky's entourage for Soviet intelligence in the 1920s. Later, in the United States, he was jailed together with his wife Myra on espionage charges. He was born in Vilkaviskis, Lithuania as Abromas Sobolevicius and sometimes used the name Abraham Sobolevicius or Adolph Senin.

Soble and his wife Myra were arrested in the United States in 1957 as part of an espionage ring known as the "Mocase", subsequent to information provided by defecting NKVD agent Boris Morros. Morros named Jane Foster Zlatovski, her husband George Zlatovski, Alfred Stern, Robert Soblen, and Jacob Albam as members of the espionage ring. After their arrest, the Sobles were interviewed numerous times, Jack at the Federal Correction Facility in Danbury, Connecticut and Myra at the Women's House of Detention, in New York City, where they provided some information. They were questioned about members of the Rosenberg spy ring, but they both denied knowing many of the members. The Sobles revealed that they had traveled to Russia, Lithuania, Germany, France, Switzerland, Austria, Japan, Canada, and the United States on behalf of Soviet intelligence. On a mission to gather intelligence on Stalin opponent Leon Trotsky, Jack visited Trotsky in Turkey in 1931 and in Copenhagen, Denmark a year later.

After a trial, both Jack and Myra, along with their associate Jacob Albam, were convicted on espionage charges and sentenced to prison. Myra received a 5½ year prison sentence for her role in the espionage ring. On October 8, 1957, Federal Judge Richard H. Levet, United States District Court, Southern District of New York, reduced her sentence to four years. Levet sentenced Jack to seven years in prison.

Soble's code name in Soviet intelligence and in the Venona files is ABRAM.