Born and educated in the United States, Bentley was a Communist Party of the United States of America (CPUSA) member recruited by the NKVD as a courier and run by an illegal, Jacob Golos, who became her lover. Upon his death in November 1943, Bentley’s role as a courier, making regular fortnightly trips to Washington, D.C., to collect information from a well-placed network of spies inside the administration of Franklin D. Roosevelt, was reduced and she had disagreements with the NKVD rezident, Anatoli Gorsky. Fearing that she might have been compromised by another CPUSA defector, Louis Budenz, Bentley made a tentative approach to the Federal Bureau of Investigation, offering information, and in September 1945 made a lengthy statement in which she implicated dozens of her contacts. Three years later, in July 1948, she gave evidence to a congressional subcommittee about the extent of her involvement in Soviet espionage and identified 35 other spies, including Harry Dexter White and the Rosenbergs.
Much of Bentley’s information was corroborated by VENONA, although she was never made aware of the source before she died in December 1963. For the latter part of her life, her testimony was branded the ravings of a fantasist, and her 1951 book, Out of Bondage, was condemned as unsubstantiated gossip, although the FBI knew her information to have been entirely accurate.