I. “You’re Sitting in the Big Chair . . .”

Ross Ulbricht had imagined that it might all come down to this one day. That at some point during the prodigious rise of his hot tech start-up he would be obliged to make a terrifyingly ruthless decision. Now, in early 2013, the time had arrived. The question was rather simple: Was he ready to kill someone to protect his billion-dollar company?

The technology business has long purported to change the world and make it a better place. But, in reality, there is a decidedly more cynical underside to all this euphoria. In Silicon Valley, after all, many founders will often do whatever is necessary to protect their creations—whether that means paying a hefty legal settlement to hush the people who helped hatch the idea for their company in the first place (Facebook, Square, Snapchat), callously vanquishing a co-founder (Twitter, Foursquare, Tinder), or remorselessly breaking laws and putting thousands of people out of work (Uber, Airbnb, among hundreds of others). But, for Ulbricht, the price was steeper. In order to save his beloved start-up, the Silk Road, an Amazon-like “everything store” for the Dark Web, he needed to “call on my muscle,” as he put it to one associate. He needed to have a guy whacked.

Ulbricht hadn’t intended for it to all come down to this. The Silk Road, like many start-ups, had begun simply enough, in 2011, as a college curiosity. As a rakishly handsome wanderlust kid from central Texas, Ulbricht had traveled north, away from his small life. He matriculated at Penn State University, where he studied materials science and engineering, and acquired interests not uncommon among contrarian millennials—particularly those who enter the technology business. Ulbricht, now 33, developed an affinity for Ayn Rand books and libertarian philosophy; he appeared to view the world not as it was, per se, but as he wanted it to be. Like Uber co-founder and C.E.O. Travis Kalanick, or early Facebook investor (and Donald Trump supporter) Peter Thiel, both of whom had been fans of Rand, Ulbricht adhered to a particularly defiant strain of Randian dogma: “The question isn’t who is going to let me; it’s who is going to stop me.”

In political-debate clubs and at the Corner Room diner, on campus, the young Ulbricht fixated on the ostensible inconsistencies in how the U.S. government determined what was, and was not, legal. His philosophizing relied on a particularly college-aged line of argumentation. Big Macs led to diabetes and heart attacks, he would often argue, so why was McDonald’s lawful? Cars facilitated tens of thousands of casualties per year, he noted, yet they remained highly unregulated and were capable of going several times the speed limit. The same was true with alcohol and cigarettes, which have killed millions. So why, Ulbricht provoked, were recreational drugs illegal?

To Ulbricht, it seemed like an arbitrary distinction. Weren’t people inevitably responsible for what they put in their own bodies—be it fast food, booze, cigarettes, or, say, marijuana? The real problem with the drug business, he surmised, was that it was violent and opaque. So he came up with the germ of an idea: what if there were a Web site, like Yelp, that rated buyers and sellers, so that exchanges would be fair and more transparent? There would be fewer fatal overdoses, he reasoned.

But Ulbricht wasn’t simply a precocious and edgy libertarian. He was also a gifted, self-taught computer programmer—someone who could engineer code to the whims and vicissitudes of his wildest fancies. And so, like many bright kids in their 20s, Ulbricht eventually headed to San Francisco to develop his company. He arrived in Silicon Valley as the peninsula was feverishly bubbling with a new wave of start-ups (Uber, Lyft, Airbnb, Slack), all of which were taking advantage of easy access to venture capital and low interest rates—and growing their valuations into the billions as they made stars of their founders.

Ulbricht’s idea for an e-commerce site that operated on the Dark Web, beyond the watchful eye of the government, may have seemed galling to some. But a new precedent was emerging in the Valley. Countless start-ups were already trying to capitalize on the legalization of marijuana in various states. Others operated in similarly opaque markets, like facilitating prostitution on pseudo dating Web sites. In Silicon Valley, indeed, pushing the letter of legality is not only admired but also financially rewarded as the very essence of “disruption.” By the time Ulbricht arrived in San Francisco, Uber and Airbnb had already staked their entire multi-billion-dollar business models on defying existing regulations, from what constituted a hotel room to who could offer a taxi ride. They were not only in heated battles with various unions but also in litigation with city governments. This new generation of Randian founders didn’t ask for permission. They just took it.

Ulbricht’s start-up, which he named the Silk Road, an homage to the ancient trade route of the Han dynasty, was no different. The Silk Road matched buyers and sellers, who shipped the product right to your door as if it were simply a hardcover book or sweater, all for a small commission. Sometimes drug dealers would take their “product” and tape it to the back of DVD cases or stuff it into hollowed-out batteries, but most drugs just appeared in a puffy envelope, undetected by federal enforcement agencies. The entire system, at least from a tech perspective, was admirably efficient.

Yet the site soon morphed from Ulbricht’s original, if naïve, plan. Despite his intent to disrupt the shady business of recreational-drug purchasing, Ulbricht saw the Silk Road become a hub for exchanging everything from hacking tools and drug-laboratory equipment to cocaine and cyanide. People soon started selling Berettas and AK-47 assault rifles, and eventually poisons that could be used to commit suicide. There were even discussions of selling body parts, such as livers and kidneys. Business was booming. Within 18 months of the operation, the Silk Road was processing $500,000 per week in sales and Ulbricht was sitting on millions in cash. If the Silk Road were valued by traditional venture capitalists, it would have been among the most successful early start-ups in Silicon Valley history. Whatever reservations Ulbricht may have had seemed quickly overwhelmed by his own ambitions to keep the site growing.

By early 2013, however, Ulbricht was encountering his first major management crisis. One Silk Road employee—a family man in central Utah, no less—had been arrested in a cocaine deal, and Ulbricht believed he’d stolen $350,000 of his money.

Ulbricht, who operated on the site under the pseudonym “Dread Pirate Roberts”—a nod to the 80s movie The Princess Bride—treated security as his top priority. He discussed everything on a secure chat application. After the alleged theft, he consulted his consigliere, a Canadian whom he had never met in real life but who operated on the Silk Road under the nom de plume “Variety Jones.” The first solution to the management crisis seemed the easiest: to simply pay the employee, Curtis Green, a visit and subsequently scare him into returning the stolen money. The second solution involved beating Green up for his treason.

But Ulbricht feared that neither option would work. His site was based on trust and scruples. If word got out on the Silk Road that users could steal hundreds of thousands of dollars without reprisal, others might skim, too. For days, Ulbricht waffled over the decision; he was, after all, just a twentysomething physics geek and coder from the Texas Hill Country. Was he really capable of violence?

After a few days, Variety Jones messaged Ulbricht: “So, you’ve had your time to think. You’re sitting in the big chair, and you need to make a decision.”

“I would have no problem wasting this guy,” Ulbricht replied.

II. The Dark Side of the Valley

For all the wonderful promise that each new technology affords, people rarely use it in the way it was intended.

When the founders of Twitter started the social network, they had one simple goal: to connect with their friends in short, concise bursts while in a loud nightclub. One hundred and forty characters and 313 million active monthly users later, the site is now incessantly infected by trolls; it is a recruiting device for ISIS and undeniably helped elect Donald Trump. Similarly, Tinder was originally intended to allow unattached college kids to meet one another and maybe go on a date. The service has since been used by chauvinists to prey on women. Facebook’s newsfeed, likewise, was infiltrated by Russian operatives who fabricated stories that were used to sway the 2016 U.S. presidential election. The nerds who first used 3-D printers wanted to make plastic wall hooks for their bedroom, or a new iPhone case for a friend. Yet from almost the moment they were introduced to the public, 3-D printers were used to build fully functional plastic guns and other weapons that can’t be picked up by a metal detector.

The Silk Road was, in many ways, no different. Ulbricht started the site to make it safer to buy pot or magic mushrooms on campus. And, like many founders in the Valley, Ulbricht simply expected people to use his creation just as he had intended. Indeed, Silicon Valley may have created more wealth than any other locus in human history, but much of that wealth has been built on the ideas of young people without much in the way of business, or life, experience. There is a reason that you don’t hear middle-aged executives say, “Move fast and break things” (Mark Zuckerberg’s famous mantra), or “Make better mistakes tomorrow” (an early Twitter motto). In fact, many tech founders now follow a familiar arc, in which they spend the first part of their careers rapidly disrupting an industry and the second part fending off lawsuits and apologizing for their actions.

Ulbricht’s story follows a similar trajectory. When he launched the Silk Road, Ulbricht had daydreamed that perhaps a few people might use it. Almost immediately, however, it became a phenomenon. When he shared his charts and graphs showing sales and revenue with Variety Jones, it was apparent that the company would earn $100 million in sales its first year. After Jones did the math, he predicted that the site would earn $1 billion in sales the following year. It might grow by a multiple of 10—or “10x” in Valley parlance—by 2014. And as the sole owner of the site, Ulbricht reaped all of the profits directly.

During the course of 2012, as Ulbricht attempted to come to terms with the scale of his creation, he formally hired Variety Jones to become his de facto C.E.O. coach, no different from the coaches Mark Zuckerberg and Steve Jobs had employed while their companies were growing so quickly, paying him as much as $60,000 per session. At first, Jones wanted to ensure that the creator of the site knew what was at stake. “Not to be a downer or anything,” Jones wrote to Ulbricht in a secure chat room on the site, but “understand that what we are doing falls under U.S. Drug Kingpin laws, which provides a maximum penalty of death upon conviction. . . . The mandatory minimum is life.”

But by that point, Ulbricht seemed concerned more with the growth of his company than with its collateral damage. Like start-up founders who eat and sleep their business, Ulbricht was unequivocally committed to the Silk Road. “Balls to the wall and all in my friend,” he replied.

Ulbricht’s quick pivot may seem remarkable, but for some inside the Valley, it fit into a larger paradigm. Once a shy kid from Texas, he had created a platform that was now being used across the world. But unlike Kalanick or, say, Airbnb’s Brian Chesky, Ulbricht was never going to be on the cover of Fast Company or Forbes. As his business grew, in fact, he was forced to become more reclusive. While Dread Pirate Roberts became the subject of stories in Forbes, Gawker, Techcrunch, and many other sites, Ulbricht operated the Silk Road anonymously from coffee shops and libraries throughout San Francisco. He hung out around Internet cafés, used dating Web sites to meet girls, and mostly kept to himself. He lived modestly in an apartment that he had found on Craigslist; he paid in cash and told his roommates that his name was “Josh,” not Ross. When family and friends wondered what he did on his computer all day, he told some he was trading currency or working on a secret project.

In a way, Ulbricht’s anonymity forced him to double down on his alter ego, Dread Pirate Roberts. The decision to murder Curtis Green was the most chilling example. Not only did Ulbricht willingly commission an $80,000 hit, but he also kept an image of Green, his jowl hanging to the side, in a folder on his computer.

At first, Ulbricht was upset about the situation, messaging the hit man he had hired that he was “a little disturbed.” Nevertheless, he soon found a way to justify his actions as a means of protecting his business. “I am pissed that he turned on me,” Ulbricht told the hit man. “I’m pissed I had to kill him. . . . I just wish more people had some integrity.”

III. “Create New Identity”

How quickly technology can change someone. Back in 2011, Ulbricht was making $300 a week as a lab researcher. He was sleeping in a basement, and his only belongings were two black garbage bags at the end of his bed, one full of clean clothes, the other dirty. Then a big idea dawned on him, no different from the ideas that spawned Uber, Airbnb, Twitter, or Facebook. Just like the 10,000 other entrepreneurs who land in San Francisco with a fantasy and a computer, Ulbricht typed lines of code and out came a world that didn’t exist before. There were no laws except his laws. He decided who was given power and who was not. In his world, he was God.

But as the Silk Road grew to become a billion-dollar business, achieving the scale that Silicon Valley start-ups dream of, Ulbricht began to grow more paranoid. He created fake identities for himself and worked on an escape plan to Dominica, a small Caribbean island nation where he felt he would be physically and financially safe. He kept most of his fortune in Bitcoin, the digital currency, and there was also some cash hidden in offshore bank accounts.

Ulbricht’s fear of being found out wasn’t hysterical. As early as June 2011, Adrian Chen, then a writer for Gawker, published a story on the Silk Road, which prompted Senator Chuck Schumer to demand that the Department of Justice take down the site. Subsequently, Ulbricht required that people who worked for him scan their real driver’s licenses or passports, to ensure they weren’t the “Feebs,” a nickname that he and Variety Jones used to refer to the feds. He added strong encryption to his computer. He started applying for citizenship in countries that would hide him and his millions. (Dominica had the best views.) He also created a checklist of what to do in the event that the “Feebs” knocked on his door. (“Find place to live on craigslist for cash; Create new identity.”) He bought fake IDs for himself on his Web site.

Ulbricht had hoped that ordering the hit on Green would bring a certain order to the Wild West that he had engineered. But it didn’t quite work out that way. Things move fast in the technology business, and within a few years the Silk Road had simply become ungovernable—it was growing so rapidly that it became a more vulnerable target. Outside hackers started knocking its servers off-line for ransom (anywhere from $10,000 to $100,000). Then others on the site became brazen and started trying to blackmail Dread Pirate Roberts.

Within a short period, Curtis Green’s murder would go from an exception to a playbook. Throughout early 2013, while tapping on his keyboard in public libraries and coffee shops, Ulbricht would hire hit men to murder drug dealers and hustlers who tried to steal from him. And while Ulbricht may have been a talented coder and fledgling manager, he was certainly not qualified to be running a criminal operation. The person whom he had hired to murder Curtis Green in Utah, as it turned out, was actually a D.E.A. agent. Green’s murder had been staged; a can of Campbell’s soup, no less, was used for gory effect. The maneuver provided the agency a powerful connection to its target, Dread Pirate Roberts.

Yet the faux hit, in some ways, also underscored a larger problem facing the Silk Road. Ulbricht wasn’t the only person vulnerable to his newfound riches. The D.E.A. agent who staged the hit had learned how to navigate the Silk Road so well during his research that he and an agent from the Secret Service would end up stealing $1.5 million from the site themselves. For all the wonderful promise that each new technology affords, indeed, people rarely ever use it in the way it was intended.

But Ulbricht’s fatal flaw would prove to be more prosaic. No matter how many experienced hackers he had hired to tighten security on the Silk Road, Ulbricht, like all programmers, made mistakes. Federal agents would eventually seize upon, among other things, an early coding error on the Silk Road that exposed the I.P. address of a coffee shop that Ulbricht frequented in San Francisco. By that point, the F.B.I., the I.R.S., the D.H.S., the D.O.J., and other agencies were all looking for Ulbricht. The I.P. address led to other revealing clues in Ulbricht’s early coding, which eventually pointed federal agents to a shaggy-haired guy quietly working away at his laptop one afternoon, in October 2013, in a library in the sleepy Glen Park area of San Francisco.

Ulbricht was found with tens of millions of dollars in Bitcoin on his laptop. Millions more had been stashed on two thumb drives sitting on his bedside table at the nearby apartment where he rented a room for $1,200 a month. He had $2 in his pocket.

IV. Move Fast and Fix Things

Ulbricht is now in prison in New York City, awaiting the results of an appeal of a double life sentence. He may be the most famous criminal in the short history of the Internet, and perhaps, as Variety Jones warned, the least likely American kingpin on record. But he is one nevertheless: this may be what Pablo Escobar looks like in the Internet Age. Ulbricht is currently housed in the same maximum-security New York City jail as the world’s most famous drug lord, “El Chapo.”

When I started reporting Ulbricht’s story, I couldn’t understand how someone had morphed so quickly and so much—and, frankly, in such an evil manner. But the more people I spoke to, the more I read of Ulbricht’s diaries—and chat logs and site comments, among other things—the more I realized that he had devolved in the exact same way as other tech entrepreneurs. The main difference was that he had chosen drugs to disrupt, rather than taxis, hotels, dating, or friendship, and that he had been held accountable for his decision to destroy other people’s lives in order to protect his business, rather than being able to look the other way, as so many successful tech C.E.O.’s do.

Those who support Ulbricht (and there are many) continue to argue that he achieved his goal, showing how drugs sold legally can save lives and make the world a better place. They have a point. In 2014, the year before Ulbricht was sentenced to life in prison, a group of university researchers concluded that the rise of online drug buying could create a safer environment for recreational usage, and subsequent studies have come to similar conclusions. Another study released in 2016 by the Centers for Disease Control and Prevention, however, noted that easy access to drugs had led to more deaths from heroin- and opioid-related overdoses than from gun violence for the first time in American history. The C.D.C.’s charts sure looked a lot like those that Variety Jones had studied.

Ulbricht had never imagined that his site would spawn all of these evils; he truly believed he was making the world a better place with it. I spoke to dozens of people who knew him through all phases of his life and work, and they said he was kind, compassionate, and caring. He still stopped to help old ladies across the street, surprised friends with thoughtful gifts, and always used the word “fudge” instead of “fuck” in e-mails and in conversations, even while he was running the site. But Ulbricht changed as the Silk Road did. The line between what was right and what was wrong got moved a little each day, until there was a chasm between the two and it was impossible to know where Ross Ulbricht ended and Dread Pirate Roberts began. If there was one thing that stood out, it was Ulbricht’s inability to see how his creation was being used for evil, even when he was the one committing the sin.

The generation that is building the technologies of tomorrow doesn’t always think about how its creations can be manipulated in nefarious ways. Driverless cars will surely free us up to nap or watch a movie on our commutes, and they will likely reduce the number of automobile fatalities each year. But why would North Korea or Iran build a nuclear weapon when either can drive countless cars into one another at 100 miles per hour? The same terrorizing possibility is true for artificial intelligence gone rogue, biotechnology research, and even the next generation of social networks.

We have now reached an inflection point. In the Age of Trump, Silicon Valley’s job is no longer to move fast and break things. Instead, it is to consider how its technologies can be used for horrendous evil. Sadly, Ross Ulbricht didn’t learn this until he was sentenced to spend the rest of his life in prison.

Adapted from American Kingpin: The Epic Hunt for the Criminal Mastermind Behind the Silk Road, by Nick Bilton, to be published this month by Portfolio, an imprint of Penguin Publishing Group, a division of Penguin Random House LLC; © 2017 by the author.