I was talking recently to a Russian acquaintance of mine who lives in the New York area. Years ago, he had studied engineering in Moscow and later transferred to a university here in the states. He told me that not long after moved, he got an unexpected visit from a couple of FBI agents who tried to recruit him.
They came right to his apartment and seemed to know everything about him. They had a detailed file which, among other things, included every application he had submitted to American universities. They also had a dossier on his old academic advisor back in Moscow containing intel about the research the professor was doing and the contracts he had with the Russian military. They wanted to know what he knew about this military work and then asked him to identify photographs of various equipment and instruments.