Andy Greenberg - Tracers in the Dark: The Global Hunt for the Crime Lords of Cryptocurrency

Early one fall morning in 2017, in a middle-class suburb on the outskirts of Atlanta, Chris Janczewski stood alone, inside the doorway of a home that he had not been invited to enter.

Moments earlier, armed Homeland Security Investigations agents in ballistic vests had taken positions around the tidy, two-story brick house, banged on the front door, and, when a member of the family living there opened it, swarmed inside. Janczewski, an Internal Revenue Service criminal investigator, had followed quietly behind them. Now he found himself in the foyer, at the eye of a storm of activity, watching the Homeland Security agents as they searched the premises and seized electronic devices.

They had separated the family, putting the father, an assistant principal at the local high school and the target of their investigation, in one room; his wife in another; the two kids into a third. An agent had switched on a TV and put on the cartoon Mickey Mouse Clubhouse in an attempt to distract the children from the invasion of their home and the interrogation of their parents.

Janczewski had come along on this raid only as an observer, a visiting IRS agent flown in from Washington, D.C., to watch and advise the local Homeland Security team as it executed its warrant. But it was Janczewskis investigation that had brought the agents here, to this very average-looking house with its well-kept yard among all the average-looking houses they could have been searching, anywhere in America. He had led them there based on a strange, nascent form of evidence: Janczewski had followed the strands of Bitcoins blockchain, pulling on a thread that had ultimately connected this ordinary home to a very dark place on the internet, and then connected that dark place to hundreds more men around the world. All complicit in the same massive network of unspeakable abuse. All now on Janczewskis long list of targets.

Over the previous few years, Janczewski, his partner Tigran Gambaryan, and a small group of law enforcement investigators at a growing roster of three-letter American agencies had used this newfound investigative technique, tracing a cryptocurrency that had once seemed untraceable, to crack one criminal case after anotherstarting small but ballooning into operations on an unprecedented, epic scale. Theyd followed Bitcoin transactions to identify culprits from Baltimore to Moscow to Bangkok. Theyd exposed crooked cops stealing millions. Theyd tracked down half a billion dollars in stolen funds, the fruits of a multiyear, international heist and money-laundering operation. And theyd pulled off the biggest online narcotics market takedown in history, capturing the markets creator and shutting down his bustling digital bazaar, one that had generated more than $650 million in contraband sales.

But even after all of those journeys into the depths of the cybercriminal underworld, tracing cryptocurrency had never before led them to a case quite like this one. That mornings search in the suburb near Atlanta, as Janczewski would later put it, was a proof of concept.

From where Janczewski was positioned at the front of the house, he could hear the agents speaking to the father, who responded in a broken, resigned voice. In another room, he could simultaneously hear the Homeland Security agents questioning the mans wife; she was answering that, yes, shed found certain images on her husbands computer, but hed told her hed downloaded them by accident when he was pirating music. And in the third room he could hear the two elementary-school-age childrenkids about as old as Janczewskis ownwatching TV. They asked for a snack, seemingly oblivious to the tragedy unfolding for their family.

Janczewski remembers the reality of the moment hitting him: This was a high school administrator, a husband, and a father of two. Whether he was guilty or innocent, the accusations this team of law enforcement agents were leveling against himtheir mere presence in his homewould almost certainly ruin his life.

He thought again of the extradimensional evidence that had brought them there, a tool like a digital divining rod, one that revealed a hidden layer of illicit connections underlying the visible world. He hoped, not for the last time, that it hadnt led him astray.