Hollow Nickel Case
FBI investigation concerning Russian espionage / From Wikipedia, the free encyclopedia
The Hollow Nickel Case (or the Hollow Coin) was the FBI investigation that grew out of the discovery of a container disguised as a U.S. coin and containing a coded message, eventually found to concern the espionage activities of William August Fisher (a.k.a. Rudolf Ivanovich Abel) on behalf of the Soviet Union.
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