Firm has no evidence that Romney’s tax returns were stolen

The financial firm PricewaterhouseCoopers on Wednesday said it has no evidence that a hacker group broke through their security and stole copies of Mitt Romney's tax returns. 

"We are aware of the allegations that have been made regarding improper access to our systems," the financial firm said 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."

The hackers claimed to have stolen the Republican nominee's tax forms last month in an elaborate heist. 

The hackers said they snuck into a Tennessee office of PricewaterhouseCoopers and then, after waiting for nightfall, scanned Romney's 1040 tax forms. They said they sent copies to the local Democratic and Republican Party offices.

The group demanded $1 million and threatened to release the forms to the public on Sept. 28 if PricewaterhouseCoopers failed to pay that amount.

Democrats, including President Obama, have called on Romney to release more than two years of his tax returns. They argue the public has a right to know the details of his personal finances. 

But Romney has insisted he is following the law and historical precednt by only releasing two years of returns.

Romney's campaign did not comment on the alleged break-in.

— This story was updated at 4:31 p.m.