As the depressingly relevant documentary The Spies Among Us chronicles, when Peter Keup, a German dancer and dance instructor was about 54, he learned that his long-deceased brother, Uli, was an informant for the Stasi, East Germany's terrifying and infamous secret police.

This new knowledge upended Keup's life. He got his degree and became a historian specializing in chronicling the Stasi's role in the lives of his friends, relatives, and the community, starting with his brother's betrayal of their family. Keup (and directors Jamie Coughlin Silverman and Gabriel Silverman) starts with a comparatively small family story that expands to a larger meditation on the nature of the security state.

In 1982, the Stasi, which had existed since the end of the war and the establishment of East Germany as a Soviet client-state, was perhaps at the height of its control (though it was never exactly low). Neighbors were informing on neighbors at a truly epic rate; it is asserted early in the film that it was assumed that a social group could not meet without at least one informant in their number. How the average citizen existed without paranoia making them lose their mind is beyond me - humans can adapt to a lot, be it an assumption of constant surveillance or an ability to put morality aside for the good of the State.

Keup, whose research often forces (or compels) him to sleep in the prison-turned-museum that once held him for nine months after he attempted to escape to the West, uses his own file to start this journey. Thanks to German law, what remains of the Stasi's files (the upper-level guys tried to burn them before a mob literally stormed the headquarters in 1990) is open to the public.

Keup interviews aging ex-Stasi on several levels. The almost-hilariously unrepentant Heiz Engelhardt, the sole living general and shot-caller/executor of the era, openly ignores passing any sort of moral judgement on himself. (Then again, he does seem like a true believer in the superiority of the Soviet Communist state - there's an integrity to his appalling nature... until you find out he became an international tour guide in his post-Soviet career.)

On the other hand, there's the fellow who once trained Stasi agents in the fine art of psychological warfare and is now struggling with guilt over his role in destroying the East German people by ruining lives in prison and in society as a whole.

Eventually, Keup must face (via his very patient, kind husband) that he is still possessed by an organization that no longer exists and must figure out a way to close off this chapter of his life. The Spies Among Us never lapses into the archive-archive-talking head closed loop that can plague historical docs. That's thanks to both the investigative aspect of the story, and a good balance between the subject's deeply personal nature and the realization that the informants' lives were far more crushed and complicated than he realized, which in turn forces him to confront that the most negative aspects of his life were horrifically common.