Sergei Tretyakov

Although Tretyakov died on June 13, 2010, his death was not announced until July 9, 2010. Tretyakov's wife cited cardiac arrest as the probable cause of death and strongly denied the foul play speculations voiced in the media but called his death quite unexpected. According to the Florida medical examiner's report, Tretyakov died after choking to death on a piece of meat; a cancerous tumor was also found in his colon.

Some Russian commentators construed Russia's Prime Minister Vladimir Putin's comments about the ultimate fate that is bound to befall "traitors" made on July 24, 2010, while he was talking to reporters about the members of the 'Illegals Program', as a thinly veiled allusion to Tretyakov's death.

In his interviews published in early 2008, Tretyakov maintained that he had never had any sort of problems when he was in the KGB/SVR service, and he never requested any money from the US government; everything that he had received upon his defection was provided by the US government, on its own initiative.

In January 2008, Tretyakov gave several interviews to publicize a book of his experiences, Comrade J.: The Untold Secrets of Russia's Master Spy in America after the End of the Cold War, written by journalist Pete Earley. Earley first met Tretyakov through an FBI contact at the Ritz-Carlton in Tysons Corner, Virginia; two FBI agents and two CIA were assigned to Tretyakov as an escort. The SVR responded to the book's release by calling it "self-publicity based on treachery." The book's release in Canada was delayed by the publisher because of legal considerations, namely Tretyakov's accusation that former Progressive Conservative MP Alex Kindy was recruited by an SVR officer at the Russian embassy in Ottawa and paid several times between 1992 and 1993. When promoting his book, Tretyakov said that Russian intelligence was just as active now as in Cold War times, adding that he hoped his book would act as a "wake-up call" to Americans.

In 2007, Tretyakov and his family were granted US citizenship.

On 10 February 2001, it was revealed, with reference to "several American officials familiar with the case," that the defector "was in fact an officer in the S.V.R., Russia's foreign intelligence service, successor to the Soviet-era K.G.B." The timing of his decision was reportedly partly affected by the death of his mother in 1997, the last close family member still living in Russia the state could threaten.

In October 2000, Tretyakov disappeared with his wife, daughter, and cat. He told the SVR, in a statement, "My resignation will not harm the interests of the country." It was not until the end of January 2001 that his defection was first reported by the Associated Press. The news was then broken in the Russian media, which reported that Russia's Foreign Ministry was insisting on having a consular meeting with him to make sure he was not being forcibly kept by the US side.

Since 1995, he worked in New York in the position of SVR deputy rezident (station chief) under the diplomatic cover of first secretary at Russia's mission at the United Nations. It was later revealed that Tretyakov was a double agent, passing secrets to Washington, from around 1997.

Colonel Sergei Olegovich Tretyakov (Russian: Сергей Олегович Третьяков; 5 October 1956 in Moscow – 13 June 2010) was a Russian SVR (foreign intelligence) officer, who defected to the United States in October 2000.