Political fundraiser Jeffrey Thompson holds up his hands to indicate that he won’t speak to reporters as he leaves federal court in Washington in 2014 after being charged. He pleaded guilty to two campaign-finance-related felonies. (Cliff Owen/Associated Press)

Federal prosecutors were counting on the testimony of a powerful political fundraiser to help prove that former D.C. mayor Vincent C. Gray knew about an illegal shadow campaign that helped pay for his bid to win the city’s highest office.

But the investigation of Gray’s role was delayed, and possibly aborted, because of concerns about Jeffrey E. Thompson’s credibility, recent interviews and new records show.

Investigators last year began asking questions about the ages of Thompson’s sexual partners to determine whether he had committed a crime, according to witnesses who spoke to federal agents and The Washington Post. Prosecutors also conducted interviews about money and gifts Thompson gave young men, and about whether he did so to hide sexual relationships, the witnesses told The Post.

The long-running inquiry into the illegal financing of Gray’s 2010 campaign uncovered a secret get-out-the-vote effort funded by Thompson that ran parallel to Gray’s official campaign, as well as off-the-books schemes he funded for other candidates. Thompson was a critical witness for prosecutors. He had said under oath in court that the former mayor knew of and discussed the off-the-books spending. Gray denies the allegations.

But before prosecutors could put the former mayor on trial, they had to vet the new information about Thompson’s past, according to interviews and documents. Even if his sexual encounters did not involve underage partners, they could be a serious distraction to a jury and detract from his credibility on the witness stand if defense attorneys brought them to light. If Thompson had paid to keep people quiet about his personal life, jurors could have been left to wonder if he was telling the truth about Gray, according to lawyers close to the case.

Thompson attorney Brendan V. Sullivan Jr. declined to respond to a series of questions in a letter detailing The Post’s reporting. Thompson also did not respond to a letter left for him at his last known address.

A former U.S. law enforcement official with knowledge of the investigation said that Thompson had “emissaries out there finding these young men” in significant numbers, often at parties Thompson underwrote. Federal agents had not concluded that any of them were underage, the former law enforcement official said.

Several people interviewed for this article spoke on the condition of anonymity because they were not authorized to publicly discuss the investigation.

Thompson, 61, has not been charged with any other crime since he pleaded guilty to two campaign-finance-related felonies in 2014. He is scheduled to be sentenced in June.

The office of U.S. Attorney Channing D. Phillips would not say whether the questions about Thompson’s relationships ultimately derailed the broader case against the former mayor. The case was closed in December without charges against Gray. But the investigation of Thompson sidetracked the case for months as prosecutors debated how to proceed, and as they interviewed new witnesses and reinterviewed others in Atlanta, Los Angeles and New York as well as the District, according to people questioned by federal agents and lawyers close to the case.

An email from the U.S. attorney’s witness coordinator discusses arrangements for Proteus Spann, a former associate of Jeffrey Thompson, to travel from New York to Washington.

One former Thompson associate, who had been questioned several times since 2013 about illegal political contributions and Thompson’s role, said the questions took a turn last year.

“They wanted to know if any of these characters were underage. Did I ever see him with anyone underage?” said Proteus Spann, a producer and former Thompson associate who was interviewed at least four times in the shadow-campaign case, most recently at the U.S. attorney’s office in Washington in June. Spann said he told investigators that the men were not underage.

Phillips shut down the investigation a few months after he took office, saying only that the evidence was “likely insufficient” to sustain a conviction against anyone other than the half-dozen people with direct connections to Gray’s 2010 mayoral campaign who had already pleaded guilty.

“They wanted to know if any of these characters were underage. Did I ever see him with anyone underage?” said Proteus Spann, who was interviewed at least four times in the shadow-campaign case involving Jeffrey Thompson. Spann told investigators the men were not underage. (Yana Paskova/For The Washington Post)
The plea deal

The former mayor has denied Thompson’s allegation that he knew about the shadow campaign. Gray has since begun a comeback campaign for his former D.C. Council seat, and he will be on the June 14 primary ballot.

Thompson is due in court four days before the election to be sentenced for illegally funneling more than $3 million to more than two dozen candidates over a six-year period, including more than $650,000 to Gray.

Thompson’s plea deal calls for no more than six months in prison if he fully cooperates. He could have faced up to seven years. At sentencing, prosecutors will have to tell a judge in a court memo whether they believe Thompson has been fully truthful in his dealings with the office, including in his statements about Gray, and whether Thompson should be credited for his cooperation.

The U.S. attorney’s office did not answer The Post’s specific questions about whether the expanded investigation of Thompson is continuing and was a reason prosecutors ended the campaign inquiry or whether prosecutors still believe Thompson’s account of his interactions with Gray.

In a statement, spokesman Bill Miller said the office “is not in position to respond to these questions because the cases involving Mr. Thompson and numerous other defendants remain pending in court.”

Without being more specific, Miller said the office would provide additional information at the sentencing hearings.

Ronald C. Machen Jr., who was then a U.S. attorney for the District of Columbia, left, and his temporary successor, Vincent H. Cohen Jr., leave court after an arraignment in 2014. The two were in charge of the campaign finance investigation of Jeffrey Thompson. (Sarah L. Voisin/The Washington Post)

When former U.S. attorney Ronald C. Machen Jr. left office in April 2015, he said the investigation he had started was active and would not be affected by his departure. When his interim successor, Vincent H. Cohen Jr., was passed over for the permanent job six months later, prosecutors had not yet determined whether Thompson’s actions warranted new charges, said a person familiar with the investigation.

That person said that neither Machen nor Cohen had ruled out going forward with Thompson as a main witness against Gray, even if it meant Thompson would face harsh cross-examination on the stand about his credibility. The office also considered the implications of going to trial without Thompson as a witness, that person said.

Machen and Cohen declined to comment.

In criminal cases, the government often relies on testimony from witnesses who cooperate in exchange for a chance of less jail time. It is also common for prosecutors to have to overcome juror misgivings and defense attorneys’ questions about the criminal conduct of their witnesses.

The findings of the Thompson investigation would have a bearing on the ultimate decision about whether to indict Gray, said the person familiar with the office’s thinking.

By the time Spann, the former Thompson associate, was contacted for another round of questions last spring, a new prosecutor had been added to the mix: Assistant U.S. Attorney Ari Redbord, who at the time specialized in cases involving child exploitation and sex crimes, according to emails to Spann from the U.S. attorney’s witness coordinator, who arranged Spann’s travel from New York to the District.

Prosecutors did not want surprises on the stand as they prepared for a possible trial against the 73-year-old former mayor. Investigators had to sort through various accounts about the ages of people who said they had been sexually involved with Thompson over the years. Spann insisted that all were college-age or older.

Laying out evidence

Former D.C. mayor Vincent C. Gray is photographed during an interview with The Washington Post earlier this year before announcing his run for D.C. Council. Investigators were looking into whether Gray knew about an illegal shadow campaign that helped pay for his mayoral bid. (Evelyn Hockstein/For The Washington Post)

Every calculation for how to proceed carried risks for the U.S. attorney’s office. Machen already had been criticized for the timing and terms of his plea deal with Thompson, and for a news conference he held that day. Machen’s assertion that anyone else involved should “come forward and own up” and that his office was “not going away” was widely interpreted as signaling that Gray was next.

Throughout the nearly five-year investigation, prosecutors had laid out many pieces of their case in court filings connected to the half-dozen people who pleaded guilty to felonies. Among those facing possible prison time when they are sentenced in the next three months are Gray’s former campaign driver, whose salary and sport-utility vehicle were paid for by Thompson; a longtime Gray confidant, who was one of the architects with Thompson of the shadow campaign; and a mutual friend of Thompson and Gray who helped conceal contributions that exceeded legal campaign finance limits.

What Machen and Cohen had not done in court files was spell out what additional evidence, if any, they had to prove the mayor knew about the illegal spending.

Thompson was a key witness to establish a connection. Particularly crucial was his account of his conversation with Gray during a dinner meeting at the Massachusetts Avenue apartment of public relations consultant Jeanne Clarke Harris, according to former prosecutors. Harris and Thompson were longtime business associates and friends, and as mayor, Gray had commemorated Harris’s 75th birthday with a ceremonial proclamation in the months before her role as a conduit for Thompson’s shadow-campaign money became public.

Reporter Nikita Stewart explains Jeffrey Thompson's significance in D.C. politics and connections to key figures in this 2013 video. (The Washington Post)

In the plea agreement he signed, Thompson said that during the dinner meeting, Gray presented a one-page campaign budget request and that Thompson told Gray that the money Thompson would provide would pass through Harris. Thompson also said that the money he was providing would be coordinated with the properly reported, legal campaign spending by Harris and Vernon Hawkins, a Gray confidant. Hawkins and Harris have pleaded guilty for their roles in the shadow campaign and are awaiting sentencing.

Gray’s attorney, Robert S. Bennett, made clear in public statements after Thompson’s plea hearing that he would try to undermine the businessman’s credibility as a witness who would tell prosecutors anything in exchange for a favorable deal.

Prosecutors met with Bennett in September 2014. They offered Gray a deal that would have required the former mayor to plead guilty to a single felony. Gray, who was not present for the meeting, rejected the proposal, according to a person with knowledge of the talks.

In a subsequent phone call to the U.S. attorney’s office, when an indictment appeared imminent, Bennett cautioned prosecutors to do more digging into Thompson’s personal life, according to people with knowledge of Bennett’s warning.

Bennett declined to comment.

That effort required investigators to interview new witnesses and to re-interview others, including Spann. In a series of interviews with The Post, Spann said he first met Thompson more than a decade ago when Spann was a model in the Congressional Black Caucus’s fashion show. The two became close, Spann said.

Federal investigators first interviewed him in Los Angeles, Spann said, and then flew him to the District twice in 2013 as part of their initial investigation of illegal campaign contributions. Documents obtained by The Post show that the U.S. attorney’s office arranged meetings for Spann with Assistant U.S. Attorney Ellen Chubin Epstein, a longtime fraud prosecutor who was on the case from the beginning.

‘We had fun’

Between 2006 and 2011, Spann contributed at least $24,000 to many of the same candidates Thompson had supported. Spann told investigators that these donations were aboveboard and that he had followed Thompson’s political advice because “his word was gold,” Spann said in an interview.

Spann mostly stayed out of the political side of Thompson’s life, he said. But in 2011, when Thompson knew the FBI was talking to his political associates, Spann said Thompson asked him to look into getting an expedited visa to take Harris to Brazil to avoid questioning by investigators. Harris later said in court that the original suggestion from Thompson was for five years in Brazil, and then three months. She rejected the idea.

When the questions later turned to Thompson’s background, Spann said he told federal investigators that Thompson paid him generously to take on many roles. At various times, Spann told The Post, he introduced Thompson to young men and some women. Thompson paid, sometimes directly, sometimes through Spann, to have them join their parties in places such as the now-defunct D.C. nightclub Dream and Miami’s South Beach or their trips to the National Football League’s Super Bowl and the National Basketball Association’s all-star games.

Proteus Spann poses for a portrait at his apartment in East Harlem in New York earlier this year. (Yana Paskova/For The Washington Post)

“We partied, we’d go to clubs. We’d hang out. We had fun,” Spann said. “I gave them money for their company — for being with us. Not for sex. Whatever happened behind closed doors had nothing to do with me.

“I gave them an opportunity to meet a millionaire,” Spann said. “Jeff never took advantage of anyone. They took advantage of each other.”

Thompson, whose companies did hundreds of millions of dollars in business with the city government, considered himself a mentor to many of the young people, Spann said. He helped with their college tuition and with internships. Thompson referred to them as “nephews,” Spann said, and had them call him “Uncle” — the same nickname Thompson had asked Gray to use when the businessman agreed to support his mayoral candidacy.

A real-life Olivia Pope

But Thompson also guarded his reputation. After growing up in a working-class family in Jamaica, he built one of the premier African American-owned accounting firms in the United States, and owned Chartered Health Plan, then the city government’s single largest contractor.

He was a regular presence on the D.C. social scene, for a time in the company of Alexis Herman, a secretary of labor under President Bill Clinton. Thompson was known as a behind-the-scenes political kingmaker because of his prodigious fundraising.

When one young man — a former stripper and go-go dancer — threatened to publicize what he said was his sexual relationship with Thompson, Spann said he urged the man not to come forward. Spann became Thompson’s fixer, an Olivia Pope, he said, in reference to the crisis manager played by actress Kerry Washington on the TV show “Scandal.”

In early 2012, the former dancer stood a few blocks from Thompson’s D.C. accounting firm, Thompson, Cobb, Bazilio & Associates, holding up a flier that threatened Thompson by name. He texted a photo of the flier to Spann, according to messages and photos reviewed by The Post.

Spann forwarded the photo to Thompson, alerting him: “I’m tired of dealing with this boy. Didn’t want to send u this but u must take him serious he is a nut case and he needs to go to jail,” according to texts Spann said he sent to Thompson in February 2012 that included a photo of the flier.

The former dancer described his plan to leaflet near Thompson’s office in an interview with The Post, in which he also confirmed that federal investigators had questioned him.

In March 2012, federal investigators raided Thompson’s home and offices, the first public confirmation that they were looking into the businessman’s political spending. The raid set off a nearly two-year legal battle over the government’s access to some of Thompson’s records that went to the Supreme Court.

To keep the former dancer quiet over an extended period, Thompson, sometimes directly, sometimes through Spann, paid the man’s college tuition, bought him a motorcycle and invested in his restaurant, according to interviews with Spann and the former dancer.

Federal investigators knew about the purchases, Spann said, and obtained copies of his credit card bills that also showed hotel and bar tabs from his outings with Thompson.

“They had everything,” Spann said.

The former go-go dancer said agents also had copies of his bank records, including checks from Thompson, in addition to emails and faxes the man sent to Spann and Thompson.

In May 2012, Thompson invested $27,000 in a Brooklyn cafe established by the former go-go dancer, according to the man, Spann and a copy of Thompson’s personal check that lists his former address on Trumbull Terrace NW and includes the note “final investment” on the memo line.

Questions ‘about youngsters’

Thompson began cooperating with investigators in early 2014, after the government threatened to indict him on campaign finance charges, according to officials familiar with the discussions. By the time prosecutors got in touch with Spann last spring, to bring him back to the District for more interviews, the questions were “all about youngsters,” Spann said.

Thompson’s 15-page plea deal with prosecutors prevents the office from bringing additional charges for any “non-violent offense” related to the investigation. But the agreement includes standard language that allows prosecutors to charge Thompson with “any crime of violence.” That definition, under federal law, does not include prostitution, but covers sex crimes against minors.

Spann said that he has not spoken to Thompson since shortly after the 2012 raid, and that he is hurt to have been cut off financially and emotionally. For a time, Thompson invested in Spann’s long-term project — the production of a musical and movie based on the life of E. Lynn Harris, the author of the best-selling book “Invisible Life,” about the struggles of closeted black men.

But Spann, who is African American and bisexual, said he understands why Thompson went to great lengths to shield his personal life. Spann lamented what he said “a gay or bisexual black man still goes through, especially in the financial world.”

“There’s no way that an out black man in America could have become as successful as Mr. Thompson has been in the business world and the political clout he had.”

Jennifer Jenkins, Mike DeBonis and Adam Goldman contributed to this report.