case officer vs overman

case officer

noun
  • A person assigned to manage a client's affairs. 

  • In intelligence organisations, a person who manages a network of agents. 

overman

noun
  • A person who supervises others; a supervisor, especially in a mine. 

  • A person with great powers; a superman. 

verb
  • To provide with too many personnel; overstaff. 

How often have the words case officer and overman occurred in a corpus of books? (source: Google Ngram Viewer )