Defendant Ross William Ulbricht in NY courtroom photo AP Photo/Elizabeth Wlliams Ross Ulbricht, the mastermind behind the Web's most famous black market, has run out of options and is now pleading with a judge not to send him to prison for life, Bloomberg reports.

Prosecutors said that Ulbricht was the "Dread Pirate Roberts," the person who ran the infamous online marketplace called Silk Road where people could buy just about anything, especially drugs.

Ulbricht was convicted in February. And with sentencing scheduled for May 29, Ulbricht, 31, is now asking for mercy from the court.

He sent a letter to the Manhattan federal judge asking to be spared the maximum penalty, life in prison, Bloomberg reports. In the letter he called Silk Road a "naive and costly idea."

Prosecutors said Silk Road helped transact about $200 million worth of anonymous drug sales using the virtual currency bitcoin and that drugs bought from Silk Road were linked to six overdose deaths.

Ulbricht's defense attorneys at first argued that Ulbricht was not Dread Pirate Roberts. After his conviction, they argued that Ulbricht should get a new trial because he wasn't allowed to review materials demonstrating his innocence, but a judge rejected the request for a new trial, calling evidence of Ulbricht's guilt "overwhelming."

Then they argued that Silk Road made buying drugs safer.

Although Silk Road is gone, there are other sites engaged in questionable online activities accessible through a part of the internet known as the "dark web" or "deep web."

Ulbricht's sentence could serve as a warning to those others.