I think the intelligence work referred here is not within the scope of war as defined in war criminal.
But it could be collaborator to foreign intelligence, or agent for foreign intelligence, which already is punishable. Now the knowingly or unknowingly factor is important usually is qualifying these crimes.
But it could be collaborator to foreign intelligence, or agent for foreign intelligence, which already is punishable. Now the knowingly or unknowingly factor is important usually is qualifying these crimes.