Corbett received the campaign contributions from a Pittsburgh law firm that helped coordinate an effort by the state's Democratic Party in 2004 to prove that Nader's petition signatures were invalid, the Pittsburgh Post-Gazette reported.
The newspaper said that evidence gathered in an ongoing investigation known as "Bonusgate" indicates the law firm Reed Smith LLP assisted in the challenge to Nader's petition. That has reportedly prompted the former presidential candidate to demand that Corbett return the contributions he received from the firm.
The Post-Gazette said Corbett could not be reached for comment, but quoted Nader's attorney, Oliver Hall, as saying Corbett told him he did not intend to return the contributions from Reed Smith.
"We reject any allegation that these contributions were in any way improper, either for our firm or Mr. Corbett," said Reed Smith spokeswoman Jamie Moss, noting that the firm contributes regularly to candidates of both parties.