This iteration of the hunt for the devil's doctrine itself and was presented around the first time that the widespread corrupting influences of socialism and its violent social counterparts became a public concern via the medium of public discussion.
Depending on where you are in noir the communists can be anything at all, from plain criminal mooks to dark bearded Victorian villains, or even the person next to you on the bus, the most innocent looking citizens of all. There are also the corporate types, the communists of ideology and those who have infiltrated our organisations and even our government. All of it is here, and made up for the screen.