Shortly after Councilmember David Catania (I-At Large) called for Mayor Vince Gray to resign in the wake of revelations that an off-the-books “shadow” campaign was waged on behalf of his 2010 bid, Mary Cheh (D-Ward 3) became the second member of the D.C. Council to call for the mayor to quit.

In a statement, Cheh said she was saddened to come to this position, just two weeks after she declared her support for the mayor while a guest on WPFW’s D.C. Politics Hour.

“Today, I join Councilmember Catania in calling on Mayor Gray to resign,” Cheh said. “Whether or not he knew of the massive election fraud that was taking place in his name, he is responsible for it.”

At a press conference today, Gray was peppered with questions about the future of his administration in the wake of yesterday’s guilty plea by Jeanne Clarke Harris, who admitted to running a campaign operation in 2010 that was not reported to the Office of Campaign Finance. But Gray repeatedly said he has no plans to resign.

Cheh’s statement in full:

Today, I join Councilmember Catania in calling on Mayor Gray to resign. Whether or not he knew of the massive election fraud that was taking place in his name, he is responsible for it. I cannot overemphasize the sadness that accompanies this action on my part. I came to know Vincent Gray as Chairman of the Council, and during the four year that we served together, I did not know of a single person with more integrity and commitment to the people of the District of Columbia. Indeed, that is why I endorsed him when he ran for Mayor. But the facts cannot be ignored and what has happened since has caused incalculable harm to the District. I believe that he would do a great public service if he would step aside now.

Update, 6:30 p.m.: A spokesman for Gray is rebuffing the calls to resign. “This is the kind of irresponsible talk we’ve come to expect from Councilmember Catania,” Pedro Ribeiro writes in an email. “It’s disappointing however that a constitutional scholar of CM Cheh’s caliber would call for a resignation before an investigation is complete.”

As the mayor’s office began responding to Cheh and Catania, Muriel Bowser (D-Ward 4) and Tommy Wells (D-Ward 6) became the latest member of the D.C. Council to call for Gray to step down.

Update, 7 p.m.: Contrary to earlier reports, Wells is not asking Gray to leave office, according to the Post’s Mike DeBonis and NBC4’s Tom Sherwood.