SAVAK’s counterintelligence department, headed by General Manuchehr Hashemi, had acquired an office building opposite the entrance to the Soviet embassy in order to better monitor the entrance to the embassy. On the ground floor was a doctor’s office; the rest of the building was used by SAVAK agents. Through an agent named Aliof, whom SAVAK planted in the Soviet embassy, SAVAK learned that KGB agents regularly met an Persian army liaison on Naft Avenue. A detailed analysis of the residents of Naft Avenue and its surroundings revealed that three army officers lived there. All three officers were placed under 24-hour surveillance, and it soon became clear that a man walking his dog in the evening had handed something over to a KGB agent.