Former Washington D.C. city contractor Jeffrey E. Thompson, who is currently being investigated for possible corruption, reportedly spent more than half a million dollars in secret aid to Hilary Clinton’s 2008 presidential campaign.

According to reports, Thompson independently financed efforts to reach voters in four states, including Texas. Thompson reportedly paid Troy White, a New York-based marketing executive, over $600,000 to “distribute posters, stickers and yard signs beginning in February 2008 to help raise Clinton’s profile during her primary battle with then-Sen. Barack Obama.”

The revelation came about when White plead guilty to tax charges earlier this week and court documents revealed the information regarding Thompson’s secret funding to support the Clinton campaign.

Officials who worked for Clinton during her presidential campaign maintain that they had no knowledge of what went on with White. Reports show that they were at one point approached by White, who pitched his ability to organize voters in urban areas, but they ultimately turned him down.

A statement from Lyn Utrecht, a lawyer for Clinton’s campaign, claims that the former First Lady and presidential candidate was not involved in any of this, and that the campaign officials have aided in efforts to uncover what went on between White and Thompson five years ago

“Hillary Clinton for President has cooperated fully in the matter involving Troy White,” said Utrecht. “As the court document filed in this matter clearly states, the Committee turned down Mr. White’s services. The Committee will not have any further comment in an ongoing investigation.”

The allegations against Thompson regarding the Clinton campaign go along with other allegations that he independently financed a secret campaign for then-candidate, now-D.C. Mayor Vincent C. Gray. Mayor Gray has denied any wrongdoing on his part, and Thompson has yet to be charged for either incident. White was allegedly involved in both cases with Thompson.