Story highlights Feds: Tennessee man is behind a group claiming to have Romneys' tax returns

Michael Mancil Brown is charged with wire fraud and extortion

Brown demanded $1 million not to release the pre-2010 returns, feds say

Then-presidential candidate Mitt Romney refused to release returns before 2010

A Tennessee man was indicted Wednesday, accused of making a false claim that he had obtained tax returns for then-Republican presidential candidate Mitt Romney and then trying to extort money for them, federal prosecutors said.

Michael Mancil Brown, 34, of Franklin is charged with six counts of wire fraud and six counts of extortion. It was not immediately clear Wednesday whether Brown had an attorney.

According to the indictment, Brown claimed he had accessed the computer network of the accounting firm PricewaterhouseCoopers and stolen tax returns for Romney and his wife, Ann, for some tax years before 2010.

During the 2012 presidential campaign, Romney released his 2010 and 2011 tax returns and refused to release others. The issue was a source of controversy on the campaign trail.

Brown allegedly was behind an August 2012 letter sent to the accounting firm demanding that $1 million in the digital currency Bitcoin be deposited to a specified Bitcoin account or else the Romney returns would be made public. The author of the letter also sent a flash drive that he claimed contained encrypted files of some of the Romneys' taxes.

Another letter addressed to "Interested Parties Worldwide" said those who wanted to see the records made public should contribute $1 million to a different Bitcoin account.

Letters also were sent to Democratic and Republican party offices in Franklin.

The indictment said Brown also posted on the website Pastebin.com a September 20, 2012, message claiming he had found a buyer for the tax information. The court document said the web postings included the phrase "Greetings from Dr. Evil," an apparent reference to the character in the Austin Powers spy spoof movies.