Even as "Roberts" worked hard to avoid detection, he thumbed his nose at the authorities who were chasing him.
"Illegal drugs home delivered … and our cops are clueless," "Roberts" tweeted in June.
Ulbricht's arrest cast a shadow over Bitcoin, the Internet currency at the heart of Silk Road's business model.
Bitcoin is a fast-growing virtual money. It has been championed by antigovernment crusaders as a decentralized currency not controlled by any government. Two of its most prominent backers are the Winklevoss twins, best known for their fight with Mark Zuckerberg over the founding of Facebook.
Bitcoin can be obtained through online exchanges and is used to buy games and products from Internet merchants.
Critics have questioned its value and said it is frequently used as a currency for illegal transactions.
Silk Road is "basically an EBay for drugs and other illicit goods," said Jerry Brito, a senior research fellow at the Mercatus Center at George Mason University.
In court papers, prosecutors allege that Ulbricht attempted to orchestrate two killings this year.
Ulbricht is accused of paying $80,0000 in February in an unsuccessful effort to have a former Silk Road employee killed for stealing from the company.
The hit man was actually an undercover law enforcement officer. Ulbricht allegedly wrote in an email that he wanted evidence of the killing. "Ask for a video. If they can't do that, then pictures," Ulbricht wrote, according to prosecutors in Maryland.
The undercover officers sent photographs of a staged killing, saying the employee died while being tortured.
Ulbricht allegedly responded: "I'm pissed that I had to kill him, but what's done is done.… I just can't believe he was so stupid. I just wish more people had some integrity."
Two months later, prosecutors say, Ulbricht tried to hire someone to kill a Silk Road user who was trying to extort money from him by threatening to disclose the names and email addresses of the site's users.
"In my eyes, FriendlyChemist is a liability and I wouldn't mind if he was executed," Ulbricht wrote in a private message to a potential hit man, according to the affidavit.
"I would like to put a bounty on his head if it's not too much trouble for you," Ulbricht allegedly wrote. "Necessities like this do happen from time to time for a person in my position."
When he was told the job would cost between $150,000 and $300,000, prosecutors say, Ulbricht responded: "Don't want to be a pain here but the price seems high. Not long ago, I had a clean hit done for $80,000."
They agreed on $150,000, which Ulbricht paid for in Bitcoin, prosecutors say. Officials have been unable to confirm the killing.
The Justice Department shut down the Silk Road website and seized Bitcoin with an estimated value of $3.6 million, which it called the largest-ever seizure of the virtual currency.
Ulbricht, who is being held without bail, appeared briefly Wednesday in federal court in San Francisco but did not enter a plea. He is scheduled to return to court Friday.
His arrest is a far cry from what Ulbricht pictured for his future.
Asked in a YouTube interview about what his life might be like 20 years into the future, he said, "I want to have had a substantial positive impact on the future of humanity."
Times staff writer Chris O'Brien in San Francisco contributed to this report.