New Yorker Abake Assongba has pledged to help President Obama win reelection, and as one of his 400 volunteer fundraisers, she has delivered $50,000 to the cause.

But she is also trailed by some controversy, accused in court of defrauding a businessman out of $657,000, impersonating a bank official and dodging creditors.

Assongba disputes the allegations, but the mysteries around her personal life highlight a challenge for Obama’s reelection effort and other presidential campaigns. The astronomical cost of running for the White House requires an army of bundlers, many of whom are strangers to the campaign. And as candidates quickly learn, it is no small task to woo — and vet — those citizen fundraisers.

Presidential hopefuls in the past have suffered through months of scandal-by-association when reports of tarnished donors have surfaced.

Hillary Rodham Clinton’s campaign agreed in 2007 to return $850,000 in contributions gathered by Norman Hsu after it became known he had evaded arrest on charges of leading an illegal investment scheme.

Last month, the Obama campaign said it would return $200,000 in donations from the Chicago-area brothers of a Mexican casino magnate linked to violence and corruption.

Alerted to questions about Assongba, the campaign acknowledged that it was difficult to scrutinize all of its bundlers and other donors. Officials said they would look into Assongba’s background and determine whether the campaign should return her donation.

“More than 1.3 million Americans have donated to the campaign, and we constantly review those contributions for any issues,” said campaign spokesman Ben LaBolt. “Some issues are easy to identify, others more difficult, but once an issue has been raised, we address it promptly, as we will do in this case. ”

Bundlers’ names released

Obama is the only presidential candidate this season to release a formal list of his bundlers, a move that offered more transparency but also opened his campaign to added scrutiny.

Like many other bundlers, Assongba came to the attention of the campaign because of her donations to the party.

She and her husband, Anthony J.W. DeRosa, had given $40,000 to Democratic House and Senate campaign committees starting in 2009, federal records show. Photos that previously appeared on her Facebook page show her and her husband standing shoulder to shoulder with Obama at a Democratic fundraiser in New York in May 2010.

Campaign staffers routinely check volunteer fundraisers for legal and public relations problems, using simple Internet searches and other available public records to turn up potential issues. In Assongba’s case, nothing prompted the campaign to turn her away.

But even a cursory look into her background reveals that Assongba does not fit the typical mold of a well-to-do bundler.

Assongba, who declined to comment, is dogged by a collection agency and a court order to pay more than $10,000 in unpaid rent for her former Brooklyn apartment, court records show.

In court documents, Assongba denies many of the allegations, and a lawyer she hired to handle media inquiries declined to comment. DeRosa said in an e-mail that the allegations are incorrect.

A deeper look at court records shows that a Swiss businessman has sued Assongba in Florida, accusing her of engaging in an e-mail scam to take his money. In 2009, the suit alleges, Assongba used an alias to impersonate a bank official but took funds wired by the businessman, Klaus Pusch, and used them to buy several properties and build a $2 million home in Ocala, Florida’s horse-breeding country. The court records note that a portion of the debt was resolved when some of Pusch’s money was returned to his account. Assongba has not been found guilty in the case, which is ongoing.

Assongba’s attorney in the Florida fraud case referred questions to Steven Bullock, an attorney for a charity Assongba founded, who declined to comment. In her court response to the suit, Assongba denies most of Pusch’s claims count by count, including that she used an alias or engaged in fraud.

Campaign finance experts say that no campaign can examine every donor who mails in a check but that bundlers, who have special access to the candidate and serve at times as an informal campaign cabinet, require deeper examination to protect a campaign’s integrity .

“You can’t have much of a vet for garden-variety donations,” said Kenneth Gross, an election and campaign law specialist who represents corporations and candidates. But, he added, “for the candidates who are bundling hundreds of thousands of dollars, they should go through a reasonable level of due diligence beyond a Google search.”

The decision by the Obama campaign to return the $200,000 donation from the brothers of the Mexican casino magnate came after the New York Times questioned the campaign about the link to the brother, Juan Jose Rojas Cardona.

State Department cables asserted that Cardona was suspected of orchestrating the assassination of a business rival and funneling $5 million in illegal campaign donations to Mexican politicians.

Cardona’s brothers did not respond to calls from The Washington Post seeking comment.

Assongba’s past

In Assongba’s case, her former landlord in Brooklyn, Haley Davey, said he was shocked to learn she was a presidential fundraiser. He said that she rented an apartment above his home in 2001 and that her first rent check bounced. Davey said she rented his apartment until 2004, was frequently late in paying and moved out after she failed to pay rent for five months.

“Knowing what I know about her, I wouldn’t have anything to do with her,” Davey said in an interview.

Assongba raises donations online for the charity she founded in 2007. Abake’s Foundation, according to its Web site, built a school and launched other significant humanitarian campaigns in the tiny African country of Benin.

Her husband, DeRosa, wrote on his Facebook profile that the foundation had an office in Cotonou, Benin, and a solid track record of humanitarian work.

“Our Accomplishments in West Africa are our micro loan program, motor taxi program, the construction of a school/clinic for urban children, and sustainable small livestock husbandry program,” it says.

But when a reporter for The Post visited the address the charity lists for its Benin headquarters, the office was closed. A man who said he was the foundation’s African coordinator said by telephone that the office had been closed for a time while he was ill. He declined to identify the location of the school the foundation built and said the director of the office travels frequently and was not available.

Bullock, the attorney for her charity, declined to comment.

At the Benin Embassy in Washington, diplomatic officials said they do not know of Abake’s Foundation, and they typically are aware of charities doing work in Benin.

“About this group we are not informed,” said Hector Posset, the embassy’s minister counselor. He offered a caution, saying, “We want people to know they should be careful where they are putting their money. Not everything is done for Benin people. Some are spending that money for their own good, or bad.”

During 2010 and 2011, the same period it claimed to be making contributions in Benin, the charity reported in federal tax filings that it had an annual budget of less than $25,000. Because it fell below that threshold, the foundation was not required to report its detailed finances.

Ken Berger, chief executive of Charity Navigator, the nation’s leading watchdog for nonprofit groups, cited a claim by Abake’s Foundation that it took staff on a three-week trip to Benin, saying that alone would have eaten up most of the charity’s reported budget.

“I don’t see how any of this is possible on a budget of less than $25,000,” Berger said. “There appears to be a fundamental mischaracterization.”

At the Obama campaign, officials say the staff is reviewing accusations against Assongba.

“We regularly review our procedures and strengthen them as necessary,” LaBolt said.

Research editor Alice Crites, staff writer James V. Grimaldi and correspondent Virgile Ahissou in Benin contributed to this report.