An aide to Mayor Eric Adams who served as his longtime liaison to the Turkish community and whose home was searched by the F.B.I. has been cooperating with the corruption investigation into the mayor and his 2021 campaign, according to three people with knowledge of the matter.

The cooperation of the aide, Rana Abbasova, could represent a significant development in the broad corruption inquiry, which has focused in part on whether Mr. Adams’s campaign conspired with the Turkish government to funnel illegal foreign donations into campaign coffers — and whether Mr. Adams pressured Fire Department officials to sign off on a new high-rise Turkish consulate despite safety concerns.

It was unclear what information Ms. Abbasova, the director of protocol for the Mayor’s Office for International Affairs, provided to the federal authorities. But she has been involved in or has had knowledge of some of Mr. Adams’s dealings with Turkish government officials and businessmen, according to emails. She also helped coordinate events and meetings with members of the Turkish community in New York and abroad and arranged some of his travel, accompanying him on two official trips to Turkey, records show.

Originally from Azerbaijan, Ms. Abbasova, 41, had worked for Mr. Adams for about four years in the Brooklyn borough president’s office before he became mayor. She began talking with the team of F.B.I. agents and federal prosecutors conducting the corruption investigation in the weeks after her home was searched on Nov. 2. On the same day, agents also searched the homes of the mayor’s chief fund-raiser and a former Turkish Airlines executive.

Like the mayor and others under scrutiny in the investigation, Ms. Abbasova has not been formally accused of wrongdoing. It is unclear whether she will plead guilty to any crimes in connection with her cooperation.

Her lawyer, Rachel Maimin, declined to comment on Monday, as did spokesmen for the U.S. attorney’s office and the F.B.I.

One of the lawyers representing Mr. Adams, Brendan R. McGuire, said in a statement that Ms. Abbasova’s cooperation was “not a new or meaningful development.” He noted that officials in the Adams administration had earlier shared information with federal prosecutors about what they described as improper actions taken by Ms. Abbasova after the search of her home.

“It is our understanding that Ms. Abbasova has been talking to investigators since her improper conduct was reported by the administration in November,” the statement said.

People with knowledge of the matter have said that her actions had in some way involved talking to another aide about communications.

Since the investigation became public, Mr. Adams has denied wrongdoing and said he always tells his staff to follow the law.

Four days after searching the homes of Ms. Abbasova and the others, F.B.I. agents approached Mr. Adams on the street after an event at New York University in Greenwich Village. They asked his security detail to step aside, climbed into his car with him, handed him a court-authorized warrant and seized his electronic devices. Federal agents and prosecutors have made few public moves since then.

The warrant for the search of the Brooklyn home of the mayor’s chief fund-raiser, Brianna Suggs, detailed at least some of the possible crimes that F.B.I. agents and prosecutors from the U.S. attorney’s office for the Southern District of New York were examining as part of the corruption inquiry.

It said they were seeking evidence to support potential charges that included wire fraud and wire fraud conspiracy, theft of federal funds and conspiracy to steal federal funds, as well as campaign contributions by foreign nationals and conspiracy to make such contributions.

Federal authorities also have been developing evidence to suggest that the Turkish Airlines executive, in coordination with Ms. Abbasova, helped arrange upgrades for Mr. Adams on Turkish Airlines, a company that Mr. Adams has extolled — even telling a pro-government Turkish publication in 2017 that the airline “is my way of flying.”

Ms. Abbasova, who had served Mr. Adams as a volunteer in the borough president’s office before she was hired full time in 2018, was suspended from her position as the director of protocol in the days after the search of her New Jersey home, but before that search had become public.

The mayor’s team told The New York Post that it had proactively put her on leave after discovering the improper actions cited by Mr. McGuire.

It was not publicly known at the time that on the same morning the F.B.I. searched the home of Ms. Suggs, agents also had descended on the New Jersey homes of Ms. Abbasova and Cenk Öcal, the former Turkish Airlines executive who served on the mayor’s transition team. The New York Times reported on those searches two weeks later. Mr. Öcal has repeatedly declined to comment.

After the search of Ms. Suggs’s home, agents walked out with electronic devices and a manila folder labeled “Eric Adams.”

That day, Mr. Adams had been planning to meet with federal officials in Washington about the migrant crisis, which he had characterized as an issue of existential concern to New York City. But when he learned of the raid, he canceled his public schedule and returned home. His office said at the time only that he wanted to “deal with a matter.”

When The Times reported on the raid of Ms. Abbasova’s home, Mr. Adams’s spokesman suggested she was a “junior staffer.” But she and Mr. Adams had a longstanding professional relationship.

Ms. Abbasova was educated in medicine and dentistry in Azerbaijan and Turkey before moving to the United States, where she continued her medical education and went into government service, according to an application she made to serve on a board of a charter school.

“Rana Abbasova is a proud Azerbaijani American who builds relations with many ethnic, immigrant communities,” the application said.

During Mr. Adams’s first term as borough president, Ms. Abbasova helped him make connections with Brooklyn’s small Turkish and Azerbaijani communities. She was given an office at Borough Hall.

In 2015, she traveled to Turkey with Mr. Adams on a trip paid for by the Turkish consulate and the World Tourism Forum Institute, an organization that says it aims to expand global tourism.

In 2018, Ms. Abbasova joined Mr. Adams’s paid staff as a “community coordinator,” earning $50,000 a year, according to city records. By 2021, her title had become “assistant to the compliance unit,” according to a list provided to Mr. Adams’s successor in Brooklyn, Antonio Reynoso.

In that role, “she was responsible for international relations and maintaining relationships between the borough president and stakeholders, including the Middle East and Central Asian countries, Muslim and Russian-speaking communities, and nonprofit organizations,” according to her City Hall biography.

When Mr. Adams became mayor in 2022, Ms. Abbasova moved to City Hall, working as his “director of protocol for international affairs,” a position in which she “advises and assists the mayor” and others “on diplomatic protocol and etiquette matters,” according to the biography. She was earning about $80,000 a year when she was put on leave.

The Turkish community in Brooklyn is not a sizable one, according to Social Explorer, a demographic data firm. As of 2022, there were 4,625 Turkish-born Brooklynites, making them the borough’s 38th largest group of foreign-born New Yorkers.

The role that Ms. Abbasova filled in Brooklyn no longer exists, a spokeswoman for Mr. Reynoso told The Times last year.

Ms. Abbasova worked in tandem with Mr. Öcal, the former manager in New York for Turkish Airlines, while in the borough president’s office, The Times has previously reported. Mr. Öcal had a relationship with Mr. Adams and was one of hundreds of people on his mayoral transition team.

She helped arrange a dinner Mr. Öcal attended while Mr. Adams was borough president with Turkish consular officials and board members of the Turken Foundation, a U.S. nonprofit with close ties to the government of the Turkish president, Recep Tayyip Erdogan.

She was also involved in arranging Mr. Adams’s appearance at a 2019 gala held by Turkish Airlines at the Metropolitan Club in Manhattan, where he made a brief speech.

Ms. Abbasova was also proposed as a board member in 2015 for the would-be charter school, Mentora International, which applied to operate in New York and was backed by Enver Yücel, a Turkish entrepreneur and philanthropist who has met with Mr. Adams in Turkey and in Brooklyn. New York State denied Mentora’s application, and the charter school did not open.

Federal investigators sought records related to campaign contributions from people associated with Bay Atlantic University, a nonprofit college and graduate school in Washington, D.C., founded by Mr. Yücel, in the search warrant they obtained to search the home of Ms. Suggs.

Mr. Adams’s mayoral campaign received a total of $10,000 in contributions from five employees of Bay Atlantic University on Sept. 27, 2021, a week after the unveiling of the new Turkish consulate building in Manhattan, and refunded the donations the following month. After Mr. Adams won the mayoral election that November, Mr. Yücel posted a picture of them together on Instagram.

“I would cordially like to congratulate my dear friend Eric Adams for his new role as the new mayor of New York City,” the caption said.

Emma Fitzsimmons and Nicole Hong contributed reporting. Susan C. Beachy contributed research.