Vassall was identified as a potential spy after Anatoliy Golitsyn, a senior member of the KGB, defected to the United States in 1961. The KGB, worried that Vassall would be exposed, ordered him to cease operations until further notice. Another defector, Yuri Nosenko, added to the case against Vassall, but doubts about the evidence provided by both Golitsyn and Nosenko persisted. Vassall soon resumed his work. It had become obvious to his colleagues that Vassall had some other source of income, for he moved to an expensive flat in Dolphin Square, took foreign holidays, and was said to own 36 Savile Row suits. His annual expenditure was later estimated at about £3,000, when his official salary was £750; but he explained that he had an inheritance from a distant relative.