The alleged Russian spy ring is news to everyone but the FBI. The bureau spent nearly a decade monitoring it, with several of the suspects’ homes searched and bugged four years ago. But officials waited to make an arrest in order to gather information about how Russian espionage works. A search five years ago revealed the spies’ steganography techniques—hiding messages in pictures—and helped the FBI crack the hidden messages sent by other couples later. The spies posed little risk of acquiring sensitive government information. Officials believe the spies were working mainly as “spotters,” or agents who identify Americans who could be recruited into working for Moscow. An unnamed event that would affect all the couples was what prompted the FBI to make arrests, officials say.