The choice was unconventional: Eric Adams, the candidate who would go on to win the 2021 election for mayor of the nation’s financial capital, had picked an inexperienced 23-year-old to run his campaign’s fund-raising operation.

Ostensibly, the fund-raiser, Brianna Suggs, did her job. Thanks in part to her work, the campaign would spend more than $18 million and win the election.

But the unusual arrangement, which raised eyebrows in the tight-knit, professional world of Democratic political fund-raising, might have come at an extraordinary cost.

On Thursday morning, federal agents raided Ms. Suggs’s home in Brooklyn and walked away with a wide range of materials, including three iPhones, two laptop computers and a manila folder labeled “Eric Adams.” The court-authorized search was part of an expansive public corruption investigation into whether the campaign conspired with the government of Turkey to receive illegal foreign donations.

Neither Ms. Suggs nor Mr. Adams has been accused of any wrongdoing. Mr. Adams has denied any knowledge of improper fund-raising, and said in a statement that his campaign would “work with officials to respond to inquiries, as appropriate — as we always have.”

Ms. Suggs, now 25 has not spoken publicly since the pre-dawn raid, and could not be reached for comment.