Robert Hanssen was a veteran FBI counterintelligence agent who decided to start selling U.S. secrets to the Soviet Union. Hanssen's spying peaked at the height of the Cold War, with his activities responsible for the deaths of at least three spies overseas. They included a Soviet Army general code-named "Top Hat," who was one of America's best intelligence sources and executed in 1986. His story, and others, are told on FOX Nation specials 'Spy Nation: Spies on the Inside' and 'Spy Nation: The Invisible Enemy', that are now available. FOX’s Eben Brown speaks with Eric O'Neill, former FBI counterintelligence and counterterrorism agent, and author of 'Gray Day' and 'Spies, Lies and Cybercrime,' who shares his personal stories about Hanssen and what he feels motivated him to turn on his own country.Click Here⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠ To Follow 'The FOX News Rundown: Evening Edition'Learn more about your ad choices. Visit podcastchoices.com/adchoices