to have been: who has been spying: trying to find out information about a government or organisation in order to give it to another govenment or organisation alleged: if you allege something you say it but do not prove it is true at the heart of: at the centre of, the most important thing counter-intelligence: the people employed by one government to prevent spying, but who are actually working in secret for an enemy government KGB: The government agency of the former USSR in charge of the Soviet political police from 1954 to 1991 betrayed: if you betray someone, you do something which harms them by helping their enemies or opponents double agents: a double agent is someone who works as a spy for a particular country or organisation, but who also works for its enemies executed: someone who has been executed has been killed as punishment for a crime Air Force One: The name of the US President's personal aircraft espionage: the activity of finding out the political or military secrets of your enemies or rivals | 
