McAfee was found dead in his jail cell in Barcelona ... just hours after the Spanish High Court ruled he could be extradited to the U.S. to face tax evasion charges.

McAfee's lawyer, Andrew Gordon, confirmed to TMZ he passed away. He had no information about the cause of death.

According to the Spanish outlet El País, McAfee was pulled from his cell and police are investigating the cause of death -- but McAfee's lawyer told Reuters the software tycoon hung himself.

McAfee had been busted in Spain back in October after years of allegedly failing to pay income taxes. A grand jury had slapped him with a 10-count federal indictment for ducking taxes from 2014 to 2018.

And, just a few months ago, McAfee was reportedly charged in Manhattan federal court for his role in a cryptocurrency scheme in which he's alleged to have bilked investors out of more than $10 million.

McAfee's death comes about a year and a half after he tweeted he was "getting subtle messages from U.S. officials saying, in effect: 'We're coming for you McAfee! We're going to kill yourself.'" He posted a photo of a "$WHACKD" tattoo he says he got on his arm, just in case. As McAfee said, "If I suicide myself, I didn't. I was whackd."

A little context here ... McAfee showed off that tat a little over 3 months after convicted sex offender Jeffrey Epstein died by suicide also while behind bars.

McAfee was briefly back on U.S. soil in 2012 after he was booted from Guatemala. He had sought asylum there after fleeing Belize ... the place he had called home since 2008. Authorities in Belize had wanted to talk to him about his neighbor's murder.

McAfee founded his antivirus software company in 1987 and he left in 1994. Intel eventually bought it in 2011 for $7.7 billion.

Three years after Intel bought the software company ... McAfee created a parody video telling users how to uninstall the software.

He founded several other tech companies, but he was always known for his self-titled antivirus software.