Having difficulty understanding how blackmail works? Need a refresher? From 1939, this Charlie Chan film is based around a blackmail operation run by a fraud psychic, who uses discreet information on people (wealthy, professional, educated and political circles especially) gathered by any and all means to coerce victims into paying out money to keep the secrets private. Substitute the fraud psychic with rogue intel agencies, racketeers, and corrupt politicians. Same tactics, same end results. It's a very old racket.
https://www.youtube.com/watch?v=2WS6I2bL8Gg&list=PLFR78Uf6Xh3h5T12nLOex2z77lxExMvhG&index=3