I believe this is based on the story of Anne Frank who was part of a Jewish family that was hiding in an attic in Amsterdam, Holland for 25 months until they were discovered by the German Secret Police.
It is alleged that the only reason they were caught was because someone tipped off the Nazis but no one has found out the identity of the person till this day. The people suggested include: Willem van Maaren, Lena Hartog, and Nelly Voskuijl
