GREENSBORO, North Carolina (CNN) -- A John Edwards donor testified Tuesday during the corruption trial of the former presidential candidate that he told the Barack Obama campaign to believe rumors of Edwards' affair as early as June 2008.
Prosecution witness Tim Toben, a developer and green energy entrepreneur, said during cross examination that during a dinner with Edwards, the candidate was optimistic about his chances of his being selected as Obama's running mate.
The message from Edwards was that if he were to be offered the position, he would take it, Toben testified.
The witness said he found the idea "astonishing," given the then-rampant rumors of Edwards' affair and child with Rielle Hunter.
After the dinner, Toben called the North Carolina director of the Obama campaign, he testified. He told it the reports about Edwards' affair were true and encouraged the campaign to vet the information thoroughly as it decided on its pick.
Edwards, who was then married, eventually admitted having had an affair with Hunter, who his campaign had hired as a videographer, and fathering her child.
Prosecutors say Edwards used donor funds to hide Hunter and their daughter in an effort to keep his candidacy viable.
Edwards broke federal law, they allege, by accepting about $725,000 from heiress Rachel "Bunny" Mellon for that purpose and more than $200,000 from Fred Baron, a now-deceased Texas lawyer who was his finance chairman.
He faces six felony courts, including conspiracy and making false statements.
Edwards' defense team has instead argued that Andrew Young, an Edwards aide, had largely used the money for his own personal gain while also paying for Hunter's medical expenses during her pregnancy. Donations for that purpose, the Edwards team has argued, cannot be considered in violation of campaign finance laws.
Young admitted during questioning that he used some donations for his own personal benefit -- particularly to fund construction of a home that included a pool and a theater.
Prosecution witness Toben also testified about an alleged sex tape involving Edwards and Hunter, which will not been shown to the jury, and whether Young had ever suggested he wanted to sell it. Young thought about selling the video, but changed his mind, Toben said.
Once a grand jury stared an investigation into the events surrounding the affair in March 2009, Toben said he sent an e-mail to Young, asking: "Wonder what that tape is worth today?"
If convicted, Edwards could face up to 30 years behind bars.