He later divulged much of the Soviet biological weapons program and settled in the United States .
Popov worked as a lead researcher at the Vector Institute from 1976 to 1986 , then at Obolensk until 1992 , when he defected to the West .
Popov later divulged much of the Soviet biological weapons program and settled in the United States .
Popov worked as a lead researcher at the Vector Institute from 1976 to 1986 , then at Obolensk until 1992 , when he defected to the West .