US President Donald Trump said he has signed a full and unconditional pardon for Ross Ulbricht, who ran Silk Road, a darknet market that sold illegal drugs.

In 2015, Ulbricht was convicted in New York of drug trafficking and money laundering conspiracy and sentenced to life in prison.

Trump posted on his Truth social platform that he had called Ulbricht’s mother to inform her that he had pardoned her son.

Silk Road, which was shut down in 2013 after police arrested Ulbricht, used Bitcoin to sell illegal drugs, as well as hacking equipment and stolen passports.

“The scumbags who tried to convict him are the same lunatics who participated in the weaponization of modern government against me,” Trump said in an online post on Tuesday night. “He was sentenced to two life sentences plus 40 years in prison. absurd!”

Ulbricht was found guilty of drug trafficking conspiracy, money laundering and computer hacking.

During the trial, prosecutors said Ulbricht’s website was hosted on the hidden “dark web” and more than $200m (£131m) worth of drugs were sold anonymously.

He ran Silk Road under the alias Dread Pirate Roberts, a reference to a character in the 1987 film The Princess Bride.

Prosecutors said he also solicited six murders for hire, including one against a former Silk Road employee, though they said there was no evidence that any murder actually occurred.

The Silk Road was named after the historical trade routes that spanned parts of Europe, Asia and Africa.

The site gained notoriety through media coverage and online discussions. But users can only access the site through Tor, a system that allows people to use the web without revealing their identity or country.

FBI court documents say the site has nearly 1 million registered users, but investigators say they don’t know how many active users there are.

Ulbricht’s sentencing – who has two university degrees – District Judge Katherine Forrest said he was “no better than any other drug dealer”.

She said the website was his “carefully planned life’s work.”

The judge noted that the lengthy sentence also sent a message to imitators that there would be “very serious consequences.”

“I want to give people the right to make choices in their lives and have the right to privacy and anonymity,” Ulbricht said at his sentencing in May 2015.

Trump previously hinted in his speech at the Libertarian Party’s national convention last year that he planned to commute Ulbricht’s sentence.

Liberals have advocated for Ulbricht’s release and said his case was an example of the government overstepping its authority.

Republican Rep. Thomas Massie, a Trump ally, praised the president’s decision.

“Thank you for keeping your word to me and others who have been advocating for Ross’s freedom,” the Kentucky congressman said.