Archconspirator

And the third archconspirator--and this is the bad one--the real archconspirator, this is the one with the pencil-thin, waxed mustache […]

The jurors listened carefully while Eidem portrayed Fern Sankey as an archconspirator who drove her husband into crime and was intimately involved in all major details of Charlie Boettcher's abduction.