Anti-virus software entrepreneur John McAfee was found dead Wednesday in his prison cell in Spain.
He faced extradition to the US to answer charges of tax evasion.
McAfee was arrested at Barcelona airport last October trying to board a flight to Istanbul.
Since then, the British-born computer programmer had been held in custody in Brians 2 jail in Sant Esteve Sesrovires.
Prison officials, who had tried to revive McAfee, said that the apparent cause of death was suicide.
"This is the result of a cruel system that had no reason to keep this man in jail for so long," McAfee's lawyer Javier Villalba told the Reuters news agency.
A court decision issued earlier on Wednesday said the tech entrepreneur should be handed over to authorities in the United States.
In a hearing held via videolink earlier this month, McAfee said the charges against him were politically motivated, arguing he would spend the rest of his life in prison if he was extradited.
What was McAfee accused of?
US prosecutors alleged the 75-year-old failed to file tax returns for four years, despite earning millions from consulting work, speaking engagements, and crypto-currencies.
Since making millions with the antivirus software in the 1980s that still bears his name, McAfee reinvented himself as a self-proclaimed Bitcoin guru.
If he had been convicted, he would have faced up to 30 years in prison.
The Securities and Exchange Commission, the US financial regulator, had also brought civil charges against McAfee.
In a filing last October, it alleged he had raked in more than $23 million (€19 million) in undisclosed income.
He always denied the allegations, taking to social media earlier this month to protest his innocence.
McAfee's personal life
The 75-year-old claimed in 2018 that he had fathered as many as 47 children.
He was married to Janice, his wife of eight years, at the time of his death.
The couple, who had no children together, met in Miami Beach when she was working as a sex worker.
McAfee had just emerged from a month on the run from murder accusations in Belize.
Authorities there had tried to implicate him in the 2012 murder of his 54-year-old neighbor, Gregory Faull.
No charges were ever brought. McAfee insisted he was innocent and the victim of a set-up.
He would later make two unsuccessful bids to enter US politics.
The tech entrepreneur, who was born in Gloucestershire in the United Kingdom, failed to win the nomination to become the Libertarian Party's candidate for the presidential elections in 2016 and 2020.
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jf/rt (AP, Reuters, AFP)