Comité para la Defensa de la Revolución.
Cuba is a state based on informers, organized all the way down to the apartment floor level.
If you got home late from a movie the busybody old lady next door wanted to know why. And of course, the system is corrupt. It isn't just counter-revolutionaries that get ratted on, but a lot of non-political grudges and vendettas are carried out this way. It leads to self-censorship, as well. Everybody is paranoid.