That year, Major Pyotr Semyonovich Popov of the GRU, contacted the CIA in Vienna, Austria, and offered to spy for the United States.
According to Kisevalter, Popov told him in April 1958 in West Berlin that he had recently overheard a drunken GRU colonel boast that the KGB knew all of the technical specifications of the top-secret Lockheed U-2 spy plane.
This information prompted James Angleton to begin an unsuccessful nine-year hunt for the "Popov's Mole" in the CIA's Soviet Russia Division.
[6] Kisevalter continued to be involved in agent recruitment and handling, including the case of the controversial English-speaking KGB walk-in, Yuri Nosenko.
Bagley and Kisevalter also interviewed Nosenko when he recontacted them in Geneva in January 1964 (two months after the assassination of President John F. Kennedy), saying he wanted to leave his wife and daughters behind in Moscow and physically defect to the U.S. because he feared that the KGB was "on to" his treason.
A few days later, Nosenko told Bagley and Kisevalter that he had to defect right then because he had just received a telegram from KGB headquarters ordering him to return to Moscow immediately.
[1] Kisevalter also briefly dealt with KGB defector Anatoliy Golitsyn when he defected to the U.S. in December 1961, and he talked him out of trying to meet with President John F. Kennedy.
[1] Kisevalter was featured in William Hood's 'skillful spy novel', Mole (1983), a presumed fictional account of the Popov operation, as the case officer Gregory Domnin.