The Parlor Maid

American citizen Katrina Leung (code name "Parlor Maid") was born in China but moved to New York (via Hong Kong) when she was 15. She was first recruited by the FBI in the late 70s and became one their top counterintelligence assets.

In 2003 Katrina was charged with being a double agent for China. Her FBI handler J.J. Smith was accused of helping her. Nobody knew they were lovers for 20 years.

One of the bureau's top Chinese counterintelligence agents, William Cleveland, was assigned to travel to China. It turns out the Chinese are aware of his visit. Cleveland had been betrayed by Parlor Maid. What the FBI didn't know was that Cleveland too had been her lover for three years.

Even after discovering Parlor Maid was a double agent, both FBI men continued to share classified information with her.

Frontline producer Michael Kirk says: "This film illustrates the lack of management controls, the failure of safeguards, the 'old boy network' and the complexities of the relationship between sources and agents that is at the heart of what the FBI does."

Frontline/PBS documentary: "From China with Love"