Vernon Hawkins is accused of lying about trying to impede an investigation into an alleged “shadow campaign,” funded by businessman Jeffrey Thompson, to back Vincent Gray’s mayoral effort. (Marvin Joseph/The Washington Post)

A D.C. political operative with long-standing ties to Mayor Vincent C. Gray was charged Monday with lying to federal authorities investigating an alleged off-the-books campaign on his behalf.

Vernon E. Hawkins, a former political adviser to Gray (D), is accused of trying to impede a sweeping probe of a secret $653,000 side effort allegedly funded by a D.C. businessman in 2010.

The case against Hawkins stems from allegations that he paid a former campaign worker to leave town to avoid FBI questions, according to court papers. He is the latest in a series of people charged who have connections to businessman Jeffrey E. Thompson, the alleged financier of what has become known as the “shadow campaign.”

Hawkins, 74, is the first person charged in the two-year investigation with a substantial link to both Gray and Thompson, who was for years one of the city’s largest contractors.

Thompson, according to court records, is the subject of a grand-jury investigation. Neither Thompson nor the mayor has been charged.

D.C. corruption scandals: A look at the investigations and where they stand.

Gray on Monday declined to discuss the charge against Hawkins, his longtime friend, who served as a consultant and adviser to Gray in his successful D.C. Council runs dating to 2004.

“It’s unfortunate to have to see something like this, and let the investigation continue,” Gray said before entering a cabinet meeting at the new Dunbar High School.

Court papers signal that Hawkins has reached a plea deal with prosecutors, and a hearing is set for Tuesday in U.S. District Court.

The charge against Hawkins carries a maximum sentence of five years in prison, but he is likely to face far less time under federal sentencing guidelines. His attorney, William E. Lawler III, declined to comment.

Another Gray campaign figure, Howard L. Brooks, pleaded guilty to the same charge last year and received a sentence that did not include prison time.

Hawkins grew up in the District and was a star football player at Armstrong Manual Training School. A city government employee starting in the 1960s, he rose from being a low-level administrator in the city’s corrections department to leading the sprawling Department of Human Services under Mayor Marion Barry in the mid-1990s.

The federal control board then overseeing the city’s budget accused Hawkins of “management failure of great magnitude” and moved to force him out in 1996. After a heated dispute between the board and Barry, Hawkins departed but denied throughout that he had mismanaged the department. “I know I’m good,” he told supporters. “But my shoulders ain’t broad enough to carry a decade of problems at DHS.”

After leaving government, Hawkins became better known for his work at Union Temple Baptist Church in Southeast and on local campaigns.

In 2010, Hawkins was among the dozens of supporters who rallied with Gray as he filed paperwork to launch his campaign. Internal campaign documents obtained by The Washington Post identified Hawkins as a “special adviser.”

Several staffers pushed Gray to distance himself from Hawkins, fearing that Gray’s opponent in the mayoral primary, incumbent Adrian M. Fenty, would use Hawkins’s presence to tie Gray to the city’s old guard, according to several people privy to the discussions about Hawkins’s role.

Hawkins remained a presence at Gray campaign headquarters, where he directed canvassers, but his name was dropped from internal documents. Campaign staffers have told The Post they were often confused by the presence of Hawkins’s own team of consultants.

Through subsequent court filings, campaign workers would learn that those canvassers worked for the “shadow campaign” that was allegedly funded by Thompson through his longtime associate Jeanne Clarke Harris.

Last year, Harris pleaded guilty to funneling Thompson’s money through companies she owned to fund the illegal side effort for Gray.

In December 2011, according to the court documents, Hawkins got money from Harris to give to another campaign worker identified in court papers only as “Person One” to try to persuade him to “leave town for an extended period of time, so that Person One would be unavailable to speak with federal agents.”

Last summer, according to prosecutors, Hawkins allegedly told FBI agents that he never asked the person to leave town and did not know anything about the money.

Person One, according to people with knowledge of the investigation, is Lamont B. Mitchell, a Hillcrest resident and the owner of a catering business. Campaign workers described Mitchell as Hawkins’s right-hand man, coordinating transportation for Thompson’s get-out-the-vote effort.

Campaign finance filings for Gray’s official campaign list a $1,800 payment to Mitchell’s Imani Catering. Mitchell has also provided catering for other candidates and council breakfast meetings.

Mitchell did not respond to messages seeking comment.

Hawkins’s connection to Thompson predates the 2010 campaign. Thompson and his companies, according to tax documents, gave more than $140,000 to the church where Hawkins was a longtime administrator in 2008 and 2009. Thompson’s Chartered Health Plan also wrote off about $200,000 in loans to the church’s nonprofit group from 2008, according to documents filed with insurance regulators.

The Rev. Willie F. Wilson, the politically active pastor of the church, said Hawkins was “very committed to the community, to people in general.”

Before leaving his church job, Wilson said, Hawkins organized its yearly summer festival, Unifest, and performed other tasks. “He’s a very dutiful and hardworking person,” he said. “He had that skill and ability to get people involved.”

Wilson said that Hawkins has continued attending the church after leaving his job but that he has not seen him for several weeks.