In the Soviet Union from the late 1950s to the 1980s, the KGB applied a form of low-intensity preventive policing, called profilaktika, to incipient threats to state security. Citizens found to be engaging in everyday political misdemeanors were invited to discuss their behaviour and to receive a warning. Such warnings were thought to be effective in stopping the citizen at risk of committing more serious state crimes from going further. This represented a complete contrast to the Stalin years, when prevention took the form of imprisonment or killing. The practice became the front line of the Soviet police state. Using a novel documentary dataset from Lithuania, a former Soviet republic, we study the profile of the private citizens who became subjects of interest to the KGB. We also investigate the philosophy, historical origins, and operational focuses of profilaktika.