5 February 1951 saw the arrival in Sydney of Vladimir Mikhaylovich Petrov, Third Secretary of the Soviet Embassy. An ASIO field officer identified Petrov as a possible 'legal', an agent of the Soviet Ministry of State Security (MGB, a forerunner to the KGB) operating under diplomatic immunity. The Organisation began gently cultivating Petrov through another agent, Dr. Michael Bialoguski, with the eventual goal of orchestrating his defection. Ultimately, Petrov was accused by the Soviet Ambassador of several lapses in judgement that would have led to his imprisonment and probable execution upon his return to the Soviet Union. Petrov feared for his life and accepted the defection life-line provided by ASIO.