Washington DC - President Donald Trump on Tuesday said he had pardoned Ross Ulbricht, the man behind the "Silk Road" online marketplace that facilitated millions of dollars of drug sales.

In 2015, Ulbricht was sentenced to life in prison after being convicted of masterminding the "dark web" platform, on which some $200 million in narcotics were sold to customers across the world.

Ulbricht, who ran Silk Road under the alias "Dread Pirate Roberts" and who had also been accused of commissioning five murders, was sentenced to two life sentences for narcotics distribution and criminal enterprise.

On the campaign trail last year, Trump had promised to free Ulbricht during a speech at the Libertarian National Convention, as he sought to gain the party's support.

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"I just called the mother of Ross William Ulbricht to let her know that in honor of her and the Libertarian Movement, which supported me so strongly, it was my pleasure to have just signed a full and unconditional pardon of her son," Trump said in a post on his Truth Social website, a day after being sworn in.

Ulbricht's case had become a cause celebre in Libertarian circles, with supporters decrying the conviction as government overreach and against the principles of free markets.

"The scum that worked to convict him were some of the same lunatics who were involved in the modern day weaponization of government against me," Trump said Tuesday.

Trump has repeatedly claimed that federal and state criminal charges filed against him were politically motivated.

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The Republican has previously vowed to impose the death penalty on drug traffickers – though the promise to free Ulbricht brought cheers from the crowd last May.

The Libertarian Party routinely runs candidates who promote both popular limited-government ideas like marijuana legalization while simultaneously pushing others like abolishing the federal tax collection agency or social security.