Funny you should mention Aldrich Ames. The New York Times reported that:
> Three years later, at the start of his career as a Russian mole, Aldrich Ames passed a Central Intelligence Agency lie detector test. In 1991, he passed another, even though he was on the agency's list of suspected moles and living at a level far above his $70,000 Government salary. Last summer, Dennis DeConcini, then chairman of the Senate Intelligence Committee, visited Mr. Ames in jail and asked how he passed the exams. "Well," Mr. Ames replied, "they don't work."
It's been a few years since I've read a book on Ames, but as far as I recall he had some plausible deniability - he claimed the money came from his father in law.
But if I recall correctly, he was also surprised it took so long.
> Three years later, at the start of his career as a Russian mole, Aldrich Ames passed a Central Intelligence Agency lie detector test. In 1991, he passed another, even though he was on the agency's list of suspected moles and living at a level far above his $70,000 Government salary. Last summer, Dennis DeConcini, then chairman of the Senate Intelligence Committee, visited Mr. Ames in jail and asked how he passed the exams. "Well," Mr. Ames replied, "they don't work."
https://www.nytimes.com/1995/02/19/opinion/lie-detectors-lie...
He also wrote a very interesting letter about polygraph testing:
https://fas.org/sgp/othergov/polygraph/ames.html