President Trump said Tuesday he had signed a full pardon for Ross Ulbricht, the founder of the scandalous online marketplace Silk Road, fulfilling a campaign promise Trump had made to Libertarian voters.

Trump posted on Truth Social that he had called Ulbricht’s mother to inform her of the pardon.

“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. He was given two life sentences, plus 40 years. Ridiculous!” Trump posted on Truth Social.

Ulbricht founded Silk Road, which served as an online black market for drugs, like heroin and cocaine, and other illicit materials. He was convicted in 2015 on seven counts related to the site, including distributing narcotics on the Internet and engaging in a continuing criminal enterprise.

Ulbricht was sentenced to life in prison, and his release had become a rallying cause for many Libertarians. Trump spoke in May at the Libertarian National Convention in Washington, where he sought to broaden his appeal by promising to commute Ulbricth’s sentence to time served on his first day in office.

“Ross Ulbricht has been a libertarian political prisoner for more than a decade. I’m proud to say that saving his life has been one of our top priorities and that has finally paid off,” Libertarian National Committee Chair Angela McArdle said in a statement on Tuesday.