A throng of media has gathered outside Mayor Vincent C. Gray’s office at the John A. Wilson Building, where he is to be deposed in an ongoing wrongful-termination lawsuit filed by a former city contract director.

Asked for comment on the recent developments of a federal probe into the Democrat’s 2010 campaign, mayoral spokesman Pedro Ribeiro said Gray (D) would not have any comment on the scheduled guilty plea of Jeanne Clarke Harris, a campaign contributor.

“He’s in there getting ready for a meeting,” Ribeiro said.

Ribeiro said the media can attend the mayor’s bi-weekly news conference Wednesday where “he’s going to be taking every question.”

Ribeiro declined to answer questions about Harris as well. “That’s a campaign matter. I don’t speak for the campaign,” he said.

Asked who did, Ribeiro said, Bob Bennett, the mayor’s personal attorney.

Harris, a public relations consultant and Gray donor, has been charged in a scheme to thwart campaign finance regulations. The 75-year-old is expected to plead guilty in U.S. District Court Tuesday to charges of funneling funds from businesses owned by businessman Jeffrey E. Thompson to her relatives, friends and employees, who then made donations to various federal and local political candidates, according to court documents and people familiar with the probe.

Thompson has not been charged. Gray has denied any wrong doing.

Gray is expected to be deposed for hours.

Eric W. Payne, who formerly worked in the Office of the Chief Financial Officer, claims he was fired after he did not steer a contract to vendors favored by D.C. Council members.

CFO Natwar M. Gandhi has said Payne was “nasty” and “rude” to others in the office, leading to his termination.

Payne has accused Gray, a former council chairman, and others of being intimately involved in the selection of a lottery vendor.

The lucrative lottery contract was politicized as teams of vendors with ties to both Gray and former mayor Adrian M. Fenty (D) competed to win the bid.