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Security Service launches investigation after recording device found in Zaluzhnyi's new office
(kyivindependent.com)
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The Russians had devices behind pictures that were undetected in the oval office during the cold war.
https://en.wikipedia.org/wiki/The_Thing_(listening_device)
"The Thing, also known as the Great Seal bug, was one of the first covert listening devices (or "bugs") to use passive techniques to transmit an audio signal. It was concealed inside a gift given by the Soviet Union to W. Averell Harriman, the United States Ambassador to the Soviet Union, on August 4, 1945. Because it was passive, needing electromagnetic energy from an outside source to become energized and active, it is considered a predecessor of radio-frequency identification (RFID) technology."