Harry Reid's accusation that Mitt Romney is hiding something by not releasing his tax returns — specifically not paying taxes for 10 years — isn't going away any time soon.

Today, Reid aide Jose Parra revealed that the source on Romney's taxes is a Republican.

This person is an investor in Bain Capital, a Republican also, and somebody who has been dealing with Romney's company for a long, long time and he has direct knowledge of this.

Previously, CNN's Dana Bash had reported, "If we knew the name, we would understand they would have the authority and the ability to know about Romney's tax returns."

Reid has received plenty of criticism for what some have called a baseless claim against Romney. The credibility of his source, if determined, could go a long way toward vindicating Reid — not to mention seriously affecting Romney's electability.

Provided Parra's claim is true, this would mean another instance of a Republican turning on Romney. Over the past two days, Romney's campaign has gotten flak from conservatives for attacking a pro-Obama ad by invoking Romney's eerily-similar-to-Obamacare Massachusetts healthcare plan.

On Fox News, Ann Coulter called for Romney to fire campaign spokesperson Andrea Paul, going so far as to say, "There is no point to us going to a convention and pushing for this man if he is employing morons like this."

Meanwhile, the Romney campaign has not responded to the new information about Reid's tax source. Earlier, they suggested Reid "put up or shut up."

UPDATE:
 Parra is already backtracking a bit. He emailed HuffPost to clarify—

I do not know the party affiliation of the source, how long he invested with Bain, or his relationship to Romney beyond the fact that he was an investor with Bain Capital, as Senator Reid has previously stated.

[Image via AP]