WASHINGTON — Former presidential candidate John Edwards met Thursday with a leading figure in the investigation into funds used to cover up his extramarital affair, certain to attract the attention of the Justice Department as it prepares possible criminal charges against him.

William Taylor, an attorney for heiress Rachel “Bunny” Mellon, confirmed they had lunch at her Upperville, Va., home but said they did not discuss the case.

“It was entirely personal and social,” Taylor said in a telephone interview. “There was no discussion of anything related to his situation.”

Mellon is the 100-year-old widow of banking heir Paul Mellon and was a top donor to Edwards’ presidential campaign. She also reportedly gave hundreds of thousands of dollars used to keep Edwards mistress Reille Hunter in hiding while he pursued the White House — funds are at the center of the criminal investigation.

The meeting was first reported Thursday by ABC News. Taylor, a prominent Washington attorney who also is representing former International Monetary Fund leader Dominique Strauss-Kahn against rape charges, said he was at the meeting and Edwards did not ask Mellon for any financial help for his case.

The meeting comes within days of the Justice Department’s plans to bring criminal charges against Edwards, a former Democratic senator from North Carolina. Prosecutors have spent two years investigating whether money from political backers, including Mellon, used to cover up his affair and out-of-wedlock daughter should have been reported as campaign contributions since they arguably aided his presidential bid.

Justice Department officials would not comment on what charges might be brought. Both sides refused to say whether a plea agreement was possible.

Edwards attorney Gregory Craig said in a statement Wednesday that prosecutors have never found that campaign funds were misused and the government’s theory in the case is without precedent and “wrong on the facts and wrong on the law.”

The investigation has centered largely on allegations leveled by former Edwards campaign aide Andrew Young, who as the scandal began to unfold in 2007 publicly claimed to be the baby’s father to protect his boss’ career.

Young has said that two wealthy Edwards supporters supplied the money and the private jet that Young used to hide Hunter from the news media, first in North Carolina, then in Colorado, and finally at a home in California.

Young has said that Edwards agreed in 2007 to solicit money directly from Mellon. Young has said he received hundreds of thousands of dollars in checks from Mellon, with some of the checks hidden in boxes of chocolate. Another Mellon attorney has said she didn’t know where the money was going but intended it as a personal gift.

Investigators also looked at money spent by Edwards’ former campaign finance chairman, Fred Baron, who died in 2008. He said he helped Young and Hunter move across the country. Baron said that Edwards wasn’t aware of the aid, but Young said in a book that Edwards knew about Baron’s money.

Hunter had been hired to shoot video of Edwards as he prepared for his White House bid. Their daughter was born in February 2008, a month after he dropped out of the race.

Edwards initially denied having an affair with Hunter but eventually admitted to it in the summer of 2008. He also denied being the father of her child before finally acknowledging that last year. His wife, Elizabeth, died of cancer in December.