According to a report from Spanish international news agency EFE, John McAfee was found dead in his prison cell at the Brians 2 Penitentiary Center on Wednesday.

Born in 1945, McAfee founded the software company McAfee Associates in his early forties. His company was responsible for one of the most well-known antivirus software programs at the time. He resigned from the company in 1994 and went on to found software firm Tribal Voice — which was behind one of the internet’s first instant message and chat programs — as well as technology company QuorumEx and security and privacy company Future Tense Central.

McAfee made headlines in the crypto space and mainstream media for a July 2017 prediction that the price of Bitcoin (BTC) would reach $500,000 by 2020. When the price of the crypto asset looked even more bullish in November 2017, McAfee doubled down, claiming that BTC would reach $1 million by 2021.

Neither prediction ultimately came true, nor did he fulfill the terms of his extravagant bet in which he claimed he would "eat [his] dick on national television" if the price did not reach $500,000. However, a nonfungible token (NFT)  animation jokingly showing the 75-year-old fulfilling his promise is available to buy through the Rarible marketplace.

The U.S. government had been seeking McAfee’s extradition for charges including failing to submit tax returns from 2014 to 2018 and allegedly not reporting income related to pushing crypto projects and consulting work. In October 2020, authorities arrested McAfee at Barcelona’s international airport, detaining him until a decision on extradition could be reached.

Related: McAfee on BTC, Exile & the US: 'No Way the Current System Can Survive’

McAfee regularly posted updates from his Twitter account, initially saying he was "content" with his situation and had friends in prison, also describing the conditions of his incarceration. One of his last messages said that he had lost the entirety of his crypto holdings and many of his friends. 

Earlier on Wednesday, a Spanish court ruled that McAfee could have been extradited to the United States following approval from the country’s Council of Ministers and the opportunity for his legal team to appeal the decision. The 75-year-old previously argued that the charges he faced were politically motivated and that if he had been extradited, he would have spent the rest of his life in prison.

We at Cointelegraph regret the loss of an iconoclastic figure like McAfee and offer our condolences to his family and friends. McAfee is survived by his wife, Janice.