Mayor Vincent Gray, shown in December 2011. (Nikki Kahn/THE WASHINGTON POST)

A close friend of Mayor Vincent C. Gray’s was charged Monday with destroying records and making illegal campaign contributions, becoming the first person incriminated in a wide-ranging federal investigation of Gray’s 2010 campaign.

The charges involve minor D.C. election law violations, but the accusations are likely to increase scrutiny of Gray’s election efforts and his term as mayor. The allegations first surfaced in March 2011, just months into Gray’s term, and have dogged him and the city since.

Reached in Las Vegas, where he is working to attract business to the District, Gray declined to comment. His office referred all calls to the mayor’s criminal defense lawyer, Robert S. Bennett, who said: “It’s a pending investigation. I don’t have any comment.”

The allegations involve one of Gray’s longtime friends and associates, Thomas W. Gore, who acted as the 2010 campaign’s assistant treasurer.

Monday’s charges came in a “criminal information,” which can be filed only with the defendant’s consent and signals a plea deal is near. Gore is expected to appear in the District’s federal court Tuesday at a “plea agreement hearing,” according to the court’s Web site. His attorney said Gore is cooperating in the criminal investigation.

Gore, 56, is accused by federal prosecutors of providing a rival candidate $535 in illegal campaign contributions in June or July of 2010 and then destroying a spiral-bound notebook that documented the payoffs. The donations were made through money orders “in the name of another person,” prosecutors said.

Court papers allege that Gore got rid of the notebook “on or about” the day The Washington Post published an article saying that minor mayoral candidate Sulaimon Brown claimed that he had received money orders from Gray’s campaign in exchange for attacks against incumbent Mayor Adrian M. Fenty.

Gray later defeated Fenty in the tightly contested Democratic primary and coasted to a general-election victory.

Gore has been charged with three D.C. election law misdemeanors and one federal charge of destroying records.

Although he could face up to 20 years in prison on the obstruction charge and a maximum penalty of six months in jail on each of the D.C. offenses, Gore is likely to serve far less prison time under federal sentencing guidelines. His attorney, Frederick D. Cooke Jr., declined to say whether his client intended to plead guilty but said, “We’re answering questions. We’re participating in a cooperative fashion. That’s all we can do.”

Gore, who did not return calls for comment, has been a friend of Gray’s for two decades and served as the treasurer of his 2004 run for a seat on the D.C. Council and his successful 2006 campaign to become the body’s chairman. In the 2010 mayoral race, he played a less prominent role because Gray and others were concerned about the perception of a conflict of interest — Gore is the former president and executive director of a nonprofit group that has received city assistance in the past.

Although Gore did not hold the title of campaign treasurer — that job belonged to one of Gray’s neighbors — he acted in that capacity and kept a tight grip on its purse strings, campaign workers have said.

On Monday morning, Gore attended a meeting of advocates working on youth-employment issues but left the meeting early, said Lori Kaplan, executive director of the Latin American Youth Center and a longtime friend.

Gore, a native Washingtonian, has been active in a consortium of youth advocates and has worked on issues involving child welfare, juvenile justice and foster care, Kaplan said.

“He has years of history doing youth and family work in this town,” Kaplan said. “These are not glamorous jobs. He’s just been really committed to this work.”

Eugene Kinlow Sr., a longtime D.C. community activist, said the charges against Gore stung because his friend has been “a pillar of the community.”

“He’s just the greatest guy,” Kinlow said. “That’s his heart. The community. . . . I know he was trying to help the mayor, but like they say, no good deed goes unpunished.”

The charges drew muted reaction at the John A. Wilson Building, in part because federal authorities have subpoenaed a number of D.C. Council offices for records related to a broadening campaign-finance investigation. But council member Tommy Wells (D-Ward 6) called the allegations “very disturbing,” and council member Mary M. Cheh (D-Ward 3) said the obstruction charge was “very serious.”

Cheh, who supported Gray’s campaign and teaches criminal law at the George Washington University law school, said the charges may signal that authorities are chasing “somebody more important” than Gore.

“Whether it’s other campaign officials, whether it goes up all the way to the mayor, I don’t know. But I do know that it’s a very significant event in the investigation,” she added.

Former federal prosecutors said it was too early to say where the investigation might be headed. But they noted that the charges are a significant milestone because they represent the first public indication that federal authorities are serious about the allegations that surfaced in March 2011 when Brown, the former candidate, told The Post that he accepted money orders and cash from the Gray campaign for attacks against Fenty. In exchange, he claimed to have been given a $110,000 job in the Gray administration. Gray countered that he never asked Brown to attack Fenty, although he acknowledged that Brown was promised a job interview.

Although court papers identified the person who received Gore’s money orders only as ”Candidate B,” sources familiar with the investigation said the recipient was Brown.

Last year, Brown alleged that the payments were made by Lorraine A. Green, the campaign’s chairwoman, and by Howard Brooks, a campaign staffer.

The contributions were made in the names of Brooks’s son, cousin-in-law and his son’s girlfriend. Both the son’s girlfriend and the cousin told The Post that they did not know Brown and did not make the contributions. Brooks’s son, Peyton, received immunity early in the investigation.

Thomas C. Green, an attorney for Lorraine Green, said, “My client has cooperated completely with the investigation, which I believe to be at an end so far as it involves her.” Glenn Ivey, an attorney for Brooks, declined to comment.

That investigation sparked by Brown’s disclosure has since broadened into an inquiry of campaign finance and ties linking a prominent D.C. contractor to local political leaders.

In March, federal agents raided the home and offices of that contractor, Jeffrey Thompson, on the same day they searched the home and office of a public relations executive involved in the Gray election effort. Former Gray campaign workers and volunteers have also been questioned by federal authorities about an off-the-books “shadow campaign” that focused on getting out the vote.

Staff writers Tim Craig, Mike DeBonis and Danielle Douglas contributed to this report. Douglas reported from Las Vegas.