WASHINGTON - A top aide to Senate Majority Leader Harry Reid (D-Nev.) provided new details Wednesday on the identity of Reid's source for the claim that Mitt Romney did not pay taxes for 10 years. Romney has since called on Reid to release the name of the source.

"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," said Reid aide Jose Parra, referring to Romney's tax returns.

Romney told ABC News that he would check his records to determine if he ever paid a lower rate than the 13.9 percent he paid in 2010. Despite requests from the network, however, Romney has yet to provide the information.

Parra teased the details in an interview with Mario Solis-Marich on KTLK’s Diverse LA radio program, according to audio of the show provided by the station.

Reid Chief of Staff David Krone previously described the source to Politico as a successful businessman, and CNN's Dana Bash reported that the source was "credible."

UPDATE: 7:08 p.m. -- Parra now says he doesn't know whether Reid's source is Republican. In an email to HuffPost, he wrote:

"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."

Related on HuffPost:

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  • Ron Paul

    "Politically, I think that would help him," Paul said in a interview with <a href="http://www.politico.com/news/stories/0712/78599.html#ixzz20w7ycTBE" target="_hplink">Politico</a>. "In the scheme of things politically, you know, it looks like releasing tax returns is what the people want."

  • Richard Lugar

    "I have no idea on why he has restricted the number to this point," <a href="http://www.cbsnews.com/8301-18563_162-57474352/pressure-mounts-on-mitt-romney-to-release-more-tax-returns/?tag=socsh" target="_hplink">Lugar said</a>.

  • George Will

    "I don't know why... he didn't get all of this out and tidy up some of his offshore accounts and all the rest," Will said on ABC's "<a href="http://www.huffingtonpost.com/2012/07/15/george-will-mitt-romney-bain_n_1674513.html?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+HP%2FPolitics+(Politics+on+The+Huffington+Post)" target="_hplink">This Week</a>." "He's done nothing illegal, nothing unseemly, nothing improper, but lots that's impolitic."

  • Bill Kristol

    "He should release the tax returns tomorrow. It's crazy," Kristol said on "<a href="http://www.huffingtonpost.com/2012/07/15/mitt-romney-tax-returns_n_1674325.html" target="_hplink">Fox News Sunday</a>." "You gotta release six, eight, 10 years of back tax returns. Take the hit for a day or two."

  • Robert Bentley

    "I just believe in total transparency," Bentley told <a href="http://abcnews.go.com/blogs/politics/2012/07/gop-governor-calls-on-mitt-romney-to-release-additional-tax-returns-and-show-he-has-nothing-to-hide/" target="_hplink">ABC News</a>. "In fact, I was asked today that question -- do you think that Governor Romney should release his tax returns? And I said I do. I said, I release my tax returns. I may be the only public official in Alabama that does, but I release mine every year and I just believe that people should release their tax returns. And if you get them out and just get past that, it just makes it so much easier."

  • Haley Barbour

    When asked on "<a href="http://www.nationaljournal.com/2012-presidential-campaign/barbour-romney-should-release-more-tax-returns-20120710" target="_hplink">The Situation Room</a>" if Romney should release more returns, Barbour said, "I would. But should it be an issue in the campaign? I don't think it amounts to diddly."

  • Michael Steele

    "If there's nothing there, there's no 'there' there, don't create a there,'" Steele said on MSNBC.

  • David Frum

    "Tax returns the next problem. Releasing returns under pressure: more weakness, more pain," Frum <a href="https://twitter.com/davidfrum/status/224509505973661696" target="_hplink">tweeted</a>.