Historians have discovered the identity of a fourth Soviet spy in the Manhattan Project. The F.B.I. evidently knew of the espionage but kept the information classified for decades.

Historians have discovered the identity of a fourth Soviet spy in the Manhattan Project. The F.B.I. evidently knew of the espionage but kept the information classified for decades. https://t.co/Kkp4kWHCZC

— New York Times World (@nytimesworld) November 23, 2019