Conspiracy of Satanists?

The question is do most Christians believe that there is a conspiracy
of Satanists many of them in positions of power who function something
like a "Star Chamber" in order to advance the devils work?

Or is it just a perception based on Faustian stories and films like
"The Omen, Rosemarys Baby and that one with Arnie in it?

And if you do believe that there is such a conspiracy then what
actually evidence is there of an actually Satanic Organization exists
and what evil actions that you know about have been performed by them?