They were accused of 'spying' for a foreign government.
a 'spy' camera/plane [=a camera/plane used for spying]
a 'spy' novel/thriller [=a novel/thriller about spies]
(..) No? Perhaps not. I've thought of a better use for you. Come along,Samwise. Keep up. Be careful,both of you. The enemy has many spies in his service: Birds,beasts. Is it safe? Never put it on... ...for the agents of the Dark Lord will be drawn to its power. Always remember,Frodo... (..)2001 The Lord of the Rings: The Fellowship of the Ring