Disclaimer. The investigations detailed in these episodes of True Spies along going,

and no formal accusations have been levied. Spies gaped as not endorse any one conclusion to the so-called

fourth man case. Welcome. Welcome. Welcome to True Spies. Week by week, mission by mission.

You'll hear the true stories behind the world's greatest espionage operations.

You'll meet the people who navigate this secret world. What do they know? What are their skills?

And what would you do in their position? This is True Spies. They had multiple

operations that were compromised that AIMS unlikely had any access to. And as it turns out,

Hanson didn't have access to them. So as the FBI told me, it's just a matter of mathematics.

I'm Vanessa Kirby, and this is True Spies. The fourth man. Part one, the big case.

The principle of need to know is a pillar of life at the CIA.

Avoid sharing information with anyone other than the people who need to know it,

and you can potentially avert a disaster down the line. That's precisely how a team of three

women at the CIA carried out a major mohunt right under the nose of their clueless boss.

I certainly didn't ask why are you coming in on weekends and why are you working on an air gap

computer which you lock up and I don't have the combination to your safe even though I'm your boss.

I just let it go. This was the mid-90s and moles were a hot topic at the CIA.

The most famous KGB infiltrator of all time had recently been arrested and convicted of espionage.

His name was Ultrich Ames. These investigators wanted to know how many losses could be blamed on

Ames and other known moles and how many were still unexplained. The three women were peeling back the

layers of secrecy and mystery to identify the known unknowns. Ames's travel to Bogota when he met

the KGB. What case went bad after that? What cases went bad in, let's say, Bulgaria when Ames is

assigned a Rome and so they can make a list of, all right, that's definitely Ames, that's definitely Ames,

...