The indictment said Brown sent similar letters to the Republican and Democratic Party offices in Tennessee, as well as to "interested parties worldwide," offering to sell the returns.

Shortly after the letter was made public on the website Pastebin, PriceWaterhouseCoopers issued a statement denying that the Romney's tax records had been obtained.

"We are aware of the allegations that have been made regarding improper access to our systems," they said then in a statement. "We are working closely with the United States Secret Service, and at this time there is no evidence that our systems have been compromised or that there was any unauthorized access to the data in question."