Mularski, the undercover FBI agent, was able to infiltrate a popular online identity theft black market, where people would buy and sell stolen credit cards, accounts, and machines used for counterfeiting. Not only was he able to grant access to the site while posing as an identity thief, he was able to eventually work his way up to administrator where he was given access to all transactions on the site as well as user information that law enforcement agencies were able to use to track down and arrest 59 people while preventing an estimated $70 million in bank fraud.

It’s quite an interesting read so be sure to read the full story.