Newly declassified documents show that the FBI kept close tabs on Soviet dictator Josef Stalin's only daughter after her high-profile defection to the US in 1967, gathering details from informants about how her arrival was affecting international relations.
The documents were released on Monday under the Freedom of Information Act following Lana Peters' death last year at age 85 in a nursing home in the state of Wisconsin.
Her defection during the cold war embarrassed the ruling communists and made her a best-selling author. Her move was also a public relations coup for the United States.
When she defected, Peters was known as Svetlana Alliluyeva, but she went by Lana Peters following her 1970 marriage to architect William Wesley Peters. Lana Peters said her defection was partly motivated by the Soviet authorities' poor treatment of her late husband, Brijesh Singh, a prominent figure in the Communist Party of India.
George Kennan, a former US ambassador to the Soviet Union and Yugoslavia, advised the FBI that he and Alliluyeva were concerned that Soviet agents would try to contact her, a December 1967 memo reveals. It notes that no security arrangements were made for her, and no other documents in the file indicate the KGB ever tracked her down.
One memo dated June 2, 1967, describes a conversation an unnamed FBI source had with Mikhail Trepykhalin, identified as the second secretary at the Soviet embassy in Washington.
The source said Trepykhalin told him the Soviets were "very unhappy over her defection" and asked whether the US would use it "for propaganda purposes".
An unnamed informant in another memo from that month said Soviet authorities were not disturbed by the defection because it would "further discredit Stalin's name and family".
Stalin, who was held responsible for sending millions of his countrymen to their deaths in labour camps, led the Soviet Union from 1924 until his death in 1953.
Even though Peters denounced communism and her father's policies, Stalin's legacy haunted her in the US.
"People say, 'Stalin's daughter, Stalin's daughter', meaning I'm supposed to walk around with a rifle and shoot the Americans," she said in a 2007 interview for a documentary about her life. "Or they say, 'No, she came here. She is an American citizen.' No, I'm neither one. I'm somewhere in between."
Many of the 233 pages released were heavily redacted.
In one exchange, a person whose name was redacted wrote to then-FBI director J Edgar Hoover, asking that he forward a letter to "Joe Stalin's daughter". The file contains Hoover's terse, three-sentence response denying his request.