" That, of course, depends entirely on who you mean by 'they'. It's a very vague term. Who is or are 'they'? Is there such a thing, are there such persons as 'they'? We don't know.

But I can tell you this. If the most popular explanation of 'they' is accepted, then these people work in very close, self-contained cells. They do that for their own security.

~Jessop "

― Agatha Christie , Destination Unknown