Eccentric antivirus software company founder John McAfee was found dead in his prison cell in Barcelona, Spain, on Wednesday, shortly after Spain’s National Court approved his extradition to the United States to face criminal tax evasion charges, Reuters reported.

The Spanish newspaper El Mundo first reported that the 75-year-old McAfee was dead.

McAfee was arrested last October at the international airport in Barcelona on those charges, which are pending in federal court in Tennessee. He had been held in jail in Spain since then.

According to the indictment, McAfee earned millions of dollars in income from promoting cryptocurrencies, consulting work, speaking engagements, and selling the rights to his life story for a documentary.

“From 2014 to 2018, McAfee allegedly failed to file tax returns, despite receiving considerable income from these sources,” the U.S. Justice Department said in October.

McAfee also was charged in Tennessee federal court in March with failing to report income he made from promoting cryptocurrencies.