brought to you by Aspire Mungfront on ITVX, a six-part drama of friendship and betrayal

starring Damien Lewis and Guy Pierce. The coldest war is within. Aspire Mungfront.

Stream-free on ITVX.

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. Here was a guy who had tried to sell loads of classified American secrets to hostile nations and had almost gotten away with it.

He was smarter than others thought he was, but he wasn't as clever as he himself thought himself to be.

This is True Spies.

Episode 104. The spy who couldn't spell.

A white, middle-aged man is walking through Poe Gahanter's State Park in Virginia, with a bulging rucksack on his back.

After a few miles he stops, checks behind him, then steps off the marked path and heads deep into the forest.

From his rucksack, he removes what looks like a full rubbish bag, smothered in duct tape, and a shovel.

Whilst he digs, Brian imagines that the next time he visits this spot to retrieve his buried treasure, he'll be $13 million better off.

This bag doesn't contain stolen jewels or even gold. It contains documents, hundreds of documents, segregated neatly into little Tupperware boxes.

These containers are full of American state secrets.

To finish, he hammers a nail into the tree closest to the fresh burial mound.

Satisfied, he walks back in the direction of the path, leaving highly classified documents, documents which could leave the United States extremely vulnerable to its enemies, just lying there in the Virginia dirt.

This is the story of how one man set out to commit an enormous act of betrayal against his country and almost got away with it.

His name is Brian Regan. He's currently languishing in an American prison with no hope of parole and strictly braver tit from speaking to anyone in the outside world except his close family.

So how do we know so much about his crimes?

Hi, my name is Utidgette Butticharji. I'm a contributing writer at National Geographic and the author of The Spy Who Couldn't Spel, which is the story of the Brian Regan espionage case.

Several years after Brian Regan was sentenced to a lifetime behind bars, Utidgette was invited to speak with an FBI crypt analyst called Daniel Olson.

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