As D.C. Mayor Vincent Gray gets ready to defend his job in the April 1 Democratic primary, PostTV looks at the highlights and low moments of his administration. (Theresa Poulson/The Washington Post)

The withdrawal of a respected newspaper’s endorsement and the launch of a new mayoral campaign posed new challenges for Mayor Vincent C. Gray’s reelection bid two days after prosecutors implicated him in a far-reaching campaign-finance scandal.

D.C. Council member David A. Catania, an independent who has won five citywide elections, filed papers to enter the November general election. And the Current newspapers, a respected chain of neighborhood weeklies, published an editorial Wednesday explaining that the scandal has “forced us to rethink” supporting the mayor.

Meanwhile, Gray showed no signs of bowing out of the fast-approaching April 1 Democratic mayoral primary, resuming a normal schedule by celebrating the city’s continuing economic boom with a groundbreaking ceremony for a long-awaited redevelopment project involving Wal-Mart near his home in Southeast Washington.

Gray also continued to push back against the allegations of businessman Jeffrey E. Thompson, who said — as part of a plea deal reached Monday with federal prosecutors — that Gray knew of a secret, off-the-books financial effort to help Gray win the mayoral election in 2010.

Among other things, a member of Gray’s Cabinet sent a letter to U.S. Attorney Ronald C. Machen Jr. challenging the suggestion that a seven-figure settlement between the city and Thompson after Gray took office was payback for Thompson’s largesse.

But other developments Wednesday may have muddied Gray’s efforts. The loss of the endorsement by the Current newspapers could have the most immediate effect. It marked the first major public defection from Gray since Thompson pleaded guilty in federal court Monday to being the mastermind of an illicit, $660,000 campaign to help elect Gray.

Gray also lost the chance to promote the support of a paper well distributed in upscale Northwest neighborhoods, where he was already not expected to do well in the April 1 primary.

The papers last week endorsed Gray, saying he had “done well in managing the city.” The editorial Wednesday took a very different tone: “[W]e question whether federal prosecutors would allege Mr. Gray knew of the illegal campaign unless they had some evidence beyond Mr. Thompson’s word. Doing so would not make sense in such a high-profile case.”

Gray’s campaign had heavily touted the endorsement, saying neighborhood papers such as the Current “have their finger on the pulse of our communities.” Gray campaign manager Chuck Thies said he told the Current that the campaign was pulling the rest of the advertising it had planned through Election Day, about $2,000 worth. “I cannot fund a business that is not courageous and yields to smear campaigns,” he said.

Catania’s entry in the race poses a longer-term challenge. It ensures that if Gray survives the primary, he will face the most serious general-election fight of any Democratic mayoral nominee in at least 20 years. Catania was first elected to the council in 1997. If elected, he would be the city’s first white, gay, onetime Republican to win the mayoralty since mayoral elections began in 1974.

As chairman of the council’s Education Committee over the past year, Catania’s push for faster school reform has defined his public image.

Standing outside the city’s election office Wednesday, Catania said the District must focus on the important issues of the future: education, caring for the city’s most vulnerable and planning for the next generation of development. “This whole drama that we’ve had, this Jeff Thompson-Vince Gray drama, the time has come for this to end,” he said.

Thies, Gray’s campaign manager, questioned the timing of Catania’s announcement. “David Catania thinks he can ride the coattails of a smear campaign into the mayor’s office,” he said. “I hope he has a new career planned because not only will he be out of a job as a council member but he also won’t be the city’s next mayor.”

The day’s developments complicated what should have been a triumphant moment for Gray: the groundbreaking of Skyland Town Center, a $220 million residential and retail development in Ward 7.

Gray led off an hour of speeches from politicians, developers and community leaders, who hailed his commitment to the project, including his role in persuading Wal-Mart to anchor the project.

Officials insisted that work was on track, although Wal-Mart hasn’t finalized a lease with the developer. Gray’s top economic development deputy, Victor B. Hoskins, said the deal would be done within weeks. Gray brushed off the suggestion that the event was an election-season spectacle, much like one staged at the Shaw’s O Street Market site in 2010 by then-Mayor Adrian M. Fenty (D), an event that Gray has often criticized.

“I don’t do premature groundbreakings,” Gray said. “I’ve been to those before.”

Wayne Turnage, Gray’s director of health-care finance, also sought to defuse a key allegation brought by prosecutors Monday — that Gray’s administration had sought to help Thompson shortly after taking office. Turnage said he sent Machen a letter Tuesday offering to meet with the top prosecutor, with “no restrictions to the questions you or others can ask.”

The letter refers to the city’s 2011 decision to settle a contractual claim with D.C. Chartered Health Plan, a Thompson-owned business and, at one time, the city’s largest contractor. Documents filed in court Monday indicated that Thompson in August 2011 asked a Gray associate, Jeanne Clarke Harris, to ask that Gray “expedite” a settlement. Harris contacted Gray, the documents said, and the settlement was finalized the next month. Fenty had resisted settling the claim, and investigators have explored whether the $7.5 million settlement was compensation for the “shadow campaign” Thompson funded on Gray’s behalf.

Gray said Monday that he did not recall being approached by Harris about a Chartered settlement. And deputies — including Turnage, D.C. Attorney General Irvin B. Nathan and others — have bristled at that line of inquiry, arguing that the settlement was justified based on the merits of Chartered’s claim. The settlement was first proposed in late June 2011, more than a month before Harris is said to have contacted Gray.

“I want to clear up what I believe is a profound misunderstanding of this issue,” Turnage wrote to Machen, saying he was ready to address, among other things, the “substance of any and all of my conversations with [Gray] about all matters related to Chartered.”

Matthew Jones, a spokesman for Machen, said the office has “received Mr. Turnage’s letter and intends to meet with him.”

Turnage — a respected administrator who worked for then-Gov. Timothy M. Kaine (D-Va.) before Kaine became a U.S. senator — has repeatedly denied being pressured by Gray to help Thompson. He said that he was interviewed last year by investigators about the settlement but that he felt compelled to send the letter to combat a “narrative that this was done as a result of some direction by the mayor.”

“People aren’t listening, or they do not believe me,” he said. “If one of the people who does not believe me is the U.S. attorney, I want to talk to him. . . . I want the opportunity to sit down with him face and face and tell him exactly what happened.”