A federal corruption investigation surrounding a Philadelphia congressman has implicated a District-based political consultant who helped D.C. Council member Muriel Bowser secure the Democratic mayoral nomination in April, according to court documents.

Tom Lindenfeld, 59, is described in documents filed last week as allegedly participating in a conspiracy in 2007 to illegally funnel $1 million to the campaign coffers of Rep. Chaka Fattah (D). Lindenfeld was working as a consultant at the time for Fattah’s unsuccessful bid for Philadelphia mayor.

The news immediately prompted Bowser (D-Ward 4) to cut ties with Lindenfeld, even though he hadn’t been working closely with her campaign since she won the April primary.

Lindenfeld is a former partner of David Axelrod, President Obama’s political guru — and one of the few politicos in Washington who moved as easily in local circles as national ones. He also advised the successful D.C. mayoral campaigns of Anthony A. Williams and Adrian M. Fenty.

Lindenfeld is not named in the court documents, but two people with knowledge of the investigation confirmed that he is the individual described as allegedly accepting a $1 million loan from a businessman and using some of it to cover Fattah campaign ­expenses. The loan was later repaid in part with federal grant money intended for “underrepresented” groups.

The two individuals requested anonymity to speak candidly about a legal matter.

Lindenfeld is described only as “Person B” and a Washington-based political consultant in a plea memorandum filed by prosecutors in U.S. District Court in Philadelphia last week, when another aide to Fattah pleaded guilty to his role in the conspiracy.

Lindenfeld has not been charged and declined to comment on the investigation. Assistant U.S. Attorney Paul L. Gray, who prosecuted the Fattah aide, also declined to comment on the case.

The lack of public documentation that Person B is Lindenfeld did not stop Bowser from issuing a strongly worded statement last week, when the Philadelphia Daily News first named Lindenfeld as the unnamed consultant described in the court papers.

Bowser said she was “quite surprised” at the allegations contained in the court papers.

“Tom is well-known for working on national and local elections, including as a consultant on my council races and in my most recent primary campaign,” she said in a statement provided to Washington City Paper on Thursday. “I have the highest expectations of transparency from my campaign team; Tom no longer has a role on the campaign.”

Bowser’s speedy reaction contrasted with her approach to other supporters who have found themselves surrounded by controversy. Bowser has resisted calls to return donations associated with Phinis Jones, a businessman involved in the controversy over the Park Southern Apartments, a troubled affordable-housing complex in Southeast Washington.

While Bowser severed ties last week, Lindenfeld had seen his role inside the campaign diminish in recent months — in part, several people familiar with the Bowser campaign said, because of tensions between Lindenfeld and others working on the campaign. The individuals were not authorized to speak publicly about internal campaign matters.

They said Lindenfeld did not tell Bowser or others involved in her campaign that he might be implicated in the Philadelphia investigation.

His critics included Fenty loyalists who distrusted Lindenfeld over his decision to air his unhappiness with Fenty’s 2010 campaign the day after his primary loss. Those critics were inflamed after Bowser’s primary victory when he garnered attention they felt was out of proportion to his role, those close to the campaign said.

On the morning of the primary, for instance, Lindenfeld was confronted by at least two Bowser supporters upset that he had invited a Washington Post reporter to accompany him to an early-morning kickoff event in Southeast Washington.

Tensions were further heightened, the people familiar with the campaign said, when Lindenfeld pursued consulting contracts with the organizers of a 2024 Olympics bid for Washington. Those talks potentially created a conflict of interest with Bowser, who has not taken a position on the Olympics bid.

To address the tensions, Lindenfeld withdrew as a paid consultant to the campaign after the primary. Lindenfeld’s firm, LSG Strategies, has collected nearly $106,000 in consulting fees from the Bowser campaign. The last payment listed in campaign finance records is dated April 15. Campaign Chairman Bill Lightfoot said in late June that Lindenfeld maintained a role as an unpaid adviser.

The activity in Philadelphia that Lindenfeld is implicated in stands at odds with his advocacy for election reforms in the District. “Pay-to-play schemes, embezzlement and all manner of insider dealing plague other cities and states,” he wrote in a 2011 Post op-ed. “But where many states have taken dramatic and effective measures to tackle corruption, the District has done very little.”

Four years prior, according to the court papers, Lindenfeld allegedly signed a promissory note for the secret $1 million loan, which was routed through Lindenfeld’s firm and then spent on campaign expenses — and not properly reported to Pennsylvania campaign finance authorities. When the unnamed businessman who gave the loan called in the debt later that year, Lindenfeld told Fattah and Greg Naylor, Fattah’s aide, according to the court papers.

One of the people with detailed knowledge of the investigation who independently confirmed that Lindenfeld is Person B said that he has seen the promissory note for the $1 million loan with Lindenfeld’s signature on it.

Naylor pleaded guilty to hiding the loan and other illegal activities and making false statements to investigators. Fattah, whose campaign has been at the center of the federal investigation, has not been charged.

The court documents did not indicate whether Lindenfeld had any knowledge of the steps taken to repay the loans, which are alleged to include the misuse of federal grants. But they do allege that he was involved in the preparation of false documents to disguise illegal shifts of money.

An attorney for Fattah, Luther E. Weaver III, declined to comment on the case. Efforts to reach Naylor and his attorney were not successful.

Paul Schwartzman contributed to this report.