The report reveals that Jeffrey Thompson, who allegedly secretly poured money into then-D.C. mayoral candidate Vincent Gray's campaign in 2010, also spent $608,000 on "street teams" tasked with passing out Clinton campaign paraphernalia in February 2008, to help improve her name recognition during the Democratic primary that year.

The street teams, according to the report, helped the Clinton effort in Texas and at least three other primary states, including North Carolina, Indiana and an unnamed fourth state. Clinton won both Indiana and Texas that year.

Neither Thompson nor the marketing executive he paid to execute the street teams, Troy White, filed any documentation of the expenditure with the Federal Election Commission — a breach of campaign finance laws.

Thompson is currently under a grand jury investigation for the role he may have played in financing a shadow mayoral campaign for Gray, but he has not yet been charged.

The expenditure came to light on Wednesday, when White plead guilty for failing to file corporate tax forms for his company, including the more than half a million dollars he received from Thompson for work for an unnamed presidential campaign.

According to court documents, White reached out to the Clinton campaign in early 2008 and offered to help organize urban voters. The campaign turned him down, but a longtime Clinton adviser, Minyon Moore, kept in touch and ultimately introduced him to Thompson, who funded his GOTV efforts.

Court documents reveal then-national political director Guy Cecil, who now works as executive director of the Democratic Senatorial Campaign Committee, knew of the initial offer. Cecil said in an an email that while "we are not going to be able to use the street teams," he was a "big fan" and hoped to "work together soon."

After White was turned down, Moore reached out again in an email to both White and Cecil to tell White that "we need your services."

“I am piping up saying we need your services.” Moore wrote to the two. “Let’s [find] some money. I will fight for it.”

White then created a GOTV plan to execute prior to the March 4 Texas primaries, and Moore connected him with Thompson to fund the campaign. Moore also helped White acquire Clinton campaign paraphernalia from the Texas campaign office, and gave him "confidential internal information" about the campaign's schedule.

Asked by a district judge whether there had been "some cooperation" between White's GOTV operation and the official campaign, he responded "yes."

An attorney for Clinton's 2008 campaign said the campaign "has cooperated fully" with the case and a senior official from the campaign said no one on senior staff was aware of the operation.

But it's the latest news that complicates Clinton's potential 2016 bid. The former secretary of State has faced continued scrutiny from Republicans for the attacks on the American consulate in Benghazi, Libya, in 2012, and questions about mismanagement at the Clinton Foundation.

She has maintained her position outside of the political sphere, for now, however, appearing only at private paid speaking engagements and a few public engagements for foundations and nonprofits close to her heart.