[2] Arriving in San Francisco in 1975, he, as an expert in semiconductors, posed as a visiting scientist at UC Berkeley where he attempted to find any useful information or possible contacts.
He revealed the existence of the KGB's Group North (Russian: группа "Север"), which was an "elite unit of senior Soviet intelligence officers who specialized in recruiting American and Canadian targets worldwide.
[2] The KGB discovered that Yuzhin was a mole in 1985, first when CIA officer Aldrich Ames identified him (as well as Valery Martinov and Sergei Motorin, KGB officers based in the Soviet embassy in Washington), and later when FBI mole Robert Hanssen confirmed that the three were working for U.S. intelligence a few months later, in his first letter to his Soviet handlers on October 1, 1985.
[1] The day before Hanssen's arrest on February 18, 2001, Yuzhin received "a cryptic call" from an FBI contact telling him to "watch the news tomorrow.
[1][4] Friends of Yuzhin's, including some longtime FBI agents who worked with him, said he lived in an attractive house he bought about five years ago in Santa Rosa, California with the money from the CIA.