A self-confessed hacker who sought a million-dollar Bitcoin payment in exchange for then-US Presidential candidate Mitt Romney's tax records has been found guilty of extortion and fraud.

In August 2012 Michael Mancil Brown, 37, sent a letter to one of Romney's accountants, PricewaterhouseCoopers (PwC), claiming to have hacked the company's servers and obtained the tax records of Romney and his wife Ann. He demanded a million-Bitcoin ransom.

At the time Romney was three months away from the presidential election and had been criticized for only releasing two years of tax returns, showing he paid about 15 per cent tax. Brown claimed to have the tax returns pre-2010 and said he offered similar terms to the local Democratic and Republican parties.

The following month, using the moniker Dr Evil, Brown put up a series of posts on Pastebin claiming that PwC's network had been physically breached on August 25. A hacking term member working in the office above had broken into a PwC terminal, extracted the files to a USB stick, and then squirrelled it out of the building.

Brown threatened a full release of the tax returns online by September 28, and said that some media firms had been sent copies but were keeping quiet about it. The Reg was contacted by Brown, but no tax records were enclosed and we advised skepticism.

Dr Evil's also said he would cancel the data dump if Romney would release his tax returns for the earlier period.

Shortly afterwards Brown's home was raided by the Feds and evidence of his contacts with the firms was recovered, with no mention of any tax returns being found. PwC has always maintained that no physical attack took place, and its IT systems weren't breached.

Now a Nashville court has found Brown/Evil guilty. "The success of this prosecution is due to the excellent online investigative skill and computer forensic analysis demonstrated repeatedly by the United States Secret Service in this era of increasingly high tech criminal conduct," said first assistant US Attorney Jack Smith.

"Hackers, aspiring hackers and identity thieves are identified, caught, prosecuted and convicted because of the work and determination of the Secret Service to stay ahead of people who abuse new technology to commit age-old crimes of fraud and extortion."

Brown was charged in 2013 and a jury has now found him guilty of six counts of wire fraud and six more of using facilities of interstate commerce to commit extortion. He faces a possible 25 years in prison and fines of up to $250,000. ®