Thompson pleaded guilty Monday to two conspiracy charges in a case that has engulfed Mayor Vincent Gray, who allegedly was the beneficiary of a "shadow campaign" organized by Thompson that helped Gray get elected in 2010.
Prosecutors have said they have no evidence that Clinton was aware of the get-out-the-vote operation.
Dewey Square, the public affairs firm where Moore works, said in a statement that Moore had "fully cooperated with the government's investigation and the facts make clear that she was entirely unaware of any inappropriate activities." The firm said Moore always conducted herself, "as she always has, not only in full compliance with the law but in accordance with the highest ethical and professional standards."
Dewey Square said Moore asked Thompson "to contribute and raise money directly for the campaign so the campaign could afford to execute a field program in constituent communities. Her actions were legal."
Polls put Clinton, the former secretary of state and New York senator, as the leading Democratic contender for president should she seek the White House again. Clinton has not said whether she will run for president but her decision has been the subject of intense speculation. Any connection to the case could provide fodder for Republicans who already are mobilizing to undercut another Clinton campaign.
Moore served as a senior adviser to Clinton's 2008 presidential campaign and is a member of the Democratic National Committee, where she once worked as chief executive officer. During President Bill Clinton's administration Moore served as political affairs director and public liaison for the White House.
Moore's purported role in the case emerged in September when Troy White, a New York marketing executive, pleaded guilty to a misdemeanor for failing to report the income received by his company, Whytehouse Marketing Inc., in the scheme.
Court documents released in White's case said the marketing executive approached a top Clinton campaign staffer about using his "street teams" to help the campaign. The staffer was Guy Cecil, Clinton's national political director in 2008, according to a person familiar with the investigation who spoke on condition of anonymity because of Cecil's limited involvement in the case.
Moore pressed Cecil to hire White in an email but Cecil declined, according to the documents and people familiar with the investigation.
In February 2008, Moore asked Thompson to fund street teams that would help Clinton's presidential campaign, according to court documents, and Moore put Thompson in contact with White "to discuss how the use of street teams could support" the campaign. The records do not identify Moore by name but she is the "individual A" listed in statement of offense signed by Thompson, according to a person familiar with the investigation who was not authorized to speak publicly on the matter.
Dewey Square said in the statement that Moore "communicated with Troy White with the understanding he was acting in compliance with campaign finance laws. Furthermore, she was never aware Jeffrey Thompson paid Troy White or any other vendor outside of the campaign."
According to the documents, Thompson authorized the transfer of more than $600,000 from two firms he controlled to a company led by political consultant Eugenia Harris, who funneled the money to White's firm to fund the street teams and canvassers. The teams were first deployed in Texas for the primary and caucus elections on March 4, 2008, followed by contests in Pennsylvania on April 22, and North Carolina and Indiana on May 6.
Three former Thompson associates have admitted in court to making more than $300,000 in straw contributions on his behalf to federal and District of Columbia candidates. One of those is Harris, the owner of Belle International Inc., the company named in court documents as having paid White.
According to a database of Thompson-affiliated donors compiled by The Associated Press, Thompson and more than 50 of his associates - including employees, relatives, business associates and friends - gave more than $100,000 to Clinton's 2008 campaign.
In preparation for the North Carolina primary, Moore sent Thompson and White an email titled, "This is what they will need in NC - Please advise," according to the documents. The email forwarded the campaign's strategy "for maximizing visibility in North Carolina," the documents show.
White responded later in the day, writing that his teams could cover several North Carolina cities, including Charlotte, Raleigh, Durham, Greensboro, Fayetteville, Wilmington and Winston-Salem.
The teams later were used in Puerto Rico for the June 1 primary, where people wore white shirts and waved signs and flags to drum up support for Clinton, according to the documents.
In a news conference Monday, U.S. Attorney Ronald Machen said Thompson's guilty plea and cooperation has opened up a "new phase" of the investigation centered on those who conspired with Thompson to subvert campaign finance laws.
"If you participated in backroom, under-the-table deals with Jeff Thompson, I urge you to come forward now and own up to your conduct," Machen said. "I promise you we are not going away."