Correction: An earlier version of this story incorrectly reported the age of D.C. Mayor Vincent Gray. He is 70, not 69, and a November fundraiser mention in the article was a celebration of his 70th birthday, not his 69th. This version has been corrected.

D.C. Mayor Vincent C. Gray is sounding like a candidate. He is acting like a candidate. Could he once again be a candidate?

A triumphal State of the District address, a brightening revenue picture and a flurry of long-term initiatives have local political observers wondering whether Gray (D), who has thus far weathered a federal investigation into his last mayoral campaign, is planning another one.

Six months ago, a reelection push was all but unthinkable for Gray after the Justice Department secured three guilty pleas in connection with his 2010 campaign and spoke openly that the investigation would continue. The District’s U.S. attorney called Gray’s win corrupted and compromised. A Washington Post poll taken at the height of the controversy found that most city residents thought Gray should resign.

But since then, visible progress in the investigation has stalled and Gray has privately told advisers recently that he is seriously considering a run. He thinks that he has amassed a solid record as mayor and has made good on key campaign promises by lowering unemployment, improving the city’s finances and fostering economic development.

Gray, 70, said he hasn’t decided whether he’ll seek a second term. “I’ll make up my mind when the spirit moves me,” he said in an interview with Washington Post reporters and editors this month, adding that it would not concern him if he were a one-term mayor.

A growing list of Gray investigations

“We’ve tried to create a framework, and if somebody has a different framework, fine — I don’t think it will be one that’s better than this,” he said. “I think we have our arms around the problems of this city.”

Besides promoting the lowering jobless rate, a proliferation of construction projects and the city’s recent $417 million budget surplus, Gray highlighted how he has been unafraid to take on difficult long-term issues such as sewer flooding in the Bloomingdale neighborhood, studying power-line burial and developing more affordable housing.

But should Gray pursue reelection, he faces serious challenges: The federal investigation continues, and the fallout has forced him to rebuild his political brain trust from scratch. Meanwhile, several D.C. Council members are openly considering challenging Gray — one, Tommy Wells (D-Ward 6), has launched an exploratory campaign; another, Jack Evans (D-Ward 2), said he is likely to run. And a new election schedule, which includes a primary in April rather than September, means Gray has less time to ponder his options.

“He needs to make up his mind soon,” said Mo Elleithee, a political consultant who worked on Gray’s 2010 campaign but who is not currently working for him. A reelection bid would be “tough but not insurmountable,” he said. “There are a lot of unanswered questions: What does the field look like? What and when is the outcome of the investigation?”

One administration official, who is not authorized to speak to the media and spoke on the condition of anonymity, said Gray “hasn’t said it himself” but said there have been high-level discussions about pursuing a reelection bid. Gray’s son, Carlos, has also discussed reelection with potential volunteers, according to two people familiar with the conversations.

A main concern should Gray move forward with a reelection bid would be replacing a campaign apparatus decimated by the federal investigation.

His 2010 campaign chairwoman, Lorraine A. Green, has been implicated in making payoffs to opposing candidate Sulaimon Brown. She has not been charged, but Thomas W. Gore, who handled financial matters for each of Gray’s campaigns going back to 2004, pleaded guilty to obstruction of justice in connection with the scheme. Vernon E. Hawkins, a key player in Gray’s D.C. Council campaigns, has been implicated, but not charged, in running an alleged “shadow campaign” — an unreported $653,000 effort on Gray’s behalf.

Key consultants on the legitimate campaign are unlikely to join a reelection effort. In the wake of the shadow campaign revelation, Elleithee and fellow strategist Steve McMahon publicly called on Gray last year to address his knowledge of the campaign irregularities, saying his reluctance to speak has “raised more questions and further eroded the public’s trust in his administration.”

Gray has not elaborated on the investigation since. He referred questions on the status of the probe to his personal attorney, Robert S. Bennett, who declined to comment Friday. But, Bennett said, “any objective observer would have to agree that the mayor is doing an excellent job.”

Like any incumbent mayor, Gray retains a base of financial support. A November fundraiser organized by Gray’s chief of staff and held to celebrate his 70th birthday offered a glimpse at who might be involved in the early stages of a reelection bid — college fraternity brothers, city contractors and lobbyists, elements of the business community and his cabinet. Of the nearly $40,000 raised for Gray’s constituent services fund, more than one-fourth came from administration officials or appointees.

“If he decides to go forward, I’d certainly support him,” said Kenneth M. Trombly, a prominent trial lawyer and a longtime friend of Gray’s who contributed at the birthday event. “My personal feeling is that he is doing a fantastic job on many, many fronts.”

But it could be difficult for Gray to raise the many hundreds of thousands of dollars more that are typically necessary for a mayoral campaign. “There’s always people who will write a check for anything if they think it’s to their advantage,” said one person involved in the 2010 campaign. “But I don’t think he can raise money.”

Assembling a team of loyal operatives, particularly volunteers, could also prove difficult. Bernadette Tolson, who was instrumental in grass-roots organizing in Ward 8 for Gray’s 2010 campaign, said she has no interest in working on the mayor’s reelection. She said she has not been asked, although she has heard from other volunteers and workers from the 2010 campaign that they have been contacted.

Although Gray appointed Tolson to the D.C. Housing Authority board, Tolson refused to lend her name to the long list of supporters for the mayor’s birthday celebration. “I told them absolutely no,” she said.

She said Gray’s chief of staff, Chris Murphy, called her and asked, “Can you just tell me why you are so adamant?”

Tolson said she explained how several former campaign workers remained out of work or in low-paying jobs despite working hard for little pay on the legitimate campaign. “When you don’t take care of the people who put you where you are, something’s wrong with that,” she said.

Another person with knowledge of the 2010 campaign criticized Murphy, accusing him of having “no political compass” as he and the mayor continue to approach those who worked for him in 2010. “This is an example of the mayor’s political naivete that got him in trouble in the first place,” said the person, who spoke on the condition of anonymity to be able to discuss matters freely.

Murphy said that the November fundraiser, which paid for toys, turkeys and other gifts, “wasn’t meant to be political” and that many campaign workers are now working ably for the administration. “The mayor remains appreciative of the hundreds of people that volunteered for his campaign,” he said.

Other 2010 supporters remain loyal: Ethel Delaney Lee, a veteran Democratic activist in vote-rich Ward 4, said she is committed to Gray even though she also considers herself a “strong supporter” of her ward’s council member, Muriel Bowser (D). Bowser is also eyeing a mayoral run.

Lee said she is sticking with Gray for personal reasons. He intervened with health officials to secure long-delayed payments for her daughter, a dentist who has treated severely handicapped residents for the city. “At this point, there is no way I couldn’t support Vincent Gray,” she said.

The person familiar with the 2010 campaign said the recent surplus made Gray feel “vindicated” and accelerated discussions about a second term. But the person advised Gray and his team to slow down: “The mayor has more serious things to resolve than running for mayor.”

Although Gray can say he made good on campaign promises about job creation, fiscal responsibility and economic development, his pledge to “restore public trust” in the mayor’s office — prompted by contracting controversies involving predecessor Adrian M. Fenty (D) — has been undermined by the campaign investigation, observers said.

Elleithee said that in 2010, Fenty campaigned on his record of getting results as mayor, but voters rejected him anyway, saying he had lost their faith and trust.

“Vince Gray is in that same situation today,” Elleithee said. “He has gotten results. . . . The economy in the District is doing much better, the budget is under control. But the people of the District have lost trust in him, and he isn’t doing anything to regain it yet. And the window is rapidly closing.”

Tim Craig contributed to this report.