" But Freeh’s FBI managed to bury the fact that its most highly valued source on Chinese espionage in the United States, a politically wired California woman named Katrina Leung, had been spying for China throughout the 1980s and 1990s. All the while, she was having sex with the special agent in charge of her case, a top supervisor of the FBI’s China Squad, James J. Smith—and occasionally with a leading FBI counterintelligence expert on China, William Cleveland. "

― Tim Weiner , Enemies: A History of the FBI