Question: Who was the United States Navy Chief Warrant Officer that was convicted for what was described as "the most damaging espionage ring uncovered in the United States in three decades?
Sentence (from "John Anthony Walker"): John Anthony Walker, Jr. (July 28, 1937 – August 28, 2014) was a United States Navy Chief Warrant Officer and communications specialist convicted of spying for the Soviet Union from 1968 to 1985.
Relevant evidence: Yes