And what did Ross have on his résumé? Two degrees and a series of dead ends.

The online world was his stage; he just needed to decide who would come out from behind the curtain.

The metamorphosis from rash young newbie to jaded old-timer had happened slowly.

With these hints, and others, he searched through the list of incoming passengers arriving at O’Hare who fit his profile. Eventually he identified an inbound passenger who he believed would be smuggling the drug.

Bone marrow, for example, sold for as much as $23,000 a gram (compared with $60 a gram for cocaine).

That evening, after the kids had been tucked into bed and kissed good night, Tarbell and Sabrina sat across from each other at the kitchen table. They both had handguns next to them in case someone tried to enter the home.

The Silk Road wasn’t just a digital drug cartel. It was a highly lucrative start-up with a lot of optionality.

The first clue: all of the smugglers had booked reservations the day before a flight. Second, the couriers used only Gmail or Yahoo! e-mail accounts. And third, they had (obviously fake) phone numbers that used a shared formula.

A little more than an hour later, at around 5:30 p.m., Preston walked out of his bedroom for what would be the last time in his life.