Not only did some communist spies become JW elders, but Watchtower has claimed (still current teaching as far as I know) that this fulfilled prophecy in Daniel 11:34.
8 Not all who professed to have an interest in serving God during the Cold War years had good motives. The angel had warned: “Many will certainly join themselves to them by means of smoothness.” (Daniel 11:34b) A considerable number showed an interest in the truth but were not willing to make a dedication to God. Yet others who seemed to accept the good news were really spies for the authorities. A report from one land reads: “Some of these unscrupulous characters were avowed Communists who had crept into the Lord’s organization, made a great display of zeal, and had even been appointed to high positions of service.”
9 The angel continued: “And some of those having insight will be made to stumble, in order to do a refining work because of them and to do a cleansing and to do a whitening, until the time of the end; because it is yet for the time appointed.” (Daniel 11:35) The infiltrators caused some faithful ones to fall into the hands of the authorities. Jehovah allowed such things to happen for a refining and a cleansing of his people. Just as Jesus “learned obedience from the things he suffered,” so these faithful ones learned endurance from the testing of their faith. (Hebrews 5:8, James 1:2, 3; compare Malachi 3:3) They are thus ‘refined, cleansed, and whitened.’
Pay Attention to Daniel’s Prophecy (1999) page 274–275.