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Leaving a Telltale Trail
In the 1980s, the KGB devised a way to track the movements of US officials with an ingenious chemical compound (nitrophenyl pentadienal) that only showed up under a special light.
Called "spy dust," it was sprinkled on doorknobs, steering wheels, and doormats. Targets unknowingly picked up the powder which left a trail that the KGB could track. |