The Police vs. Secret Police

Recently, I was talking to someone and made a distinction between the police and secret police.  And the person reacted immediately--she was well aware there was a difference between the two.  Don't recall at the moment when I first became aware of the possibility of secret police being involved in my life.  But by this time, I feel more confident to identify them.  [I've added more specific details in other notes I've written in my blogs today.]