Three years ago, as Eric Adams was running for mayor of New York City, his campaign was raking in donations from a broad range of mysterious sources.

There was the $201,330 delivered by unidentified intermediaries through 57 clusters of donations, some from people working at institutions with ties to Turkey. Their contributions are being scrutinized in a federal investigation focused in part on potentially unlawful foreign money flowing into campaign coffers.

Then there was a set of unknown bundlers who gathered donations tied to Lian Wu Shao, whose family oversees the New World Mall in downtown Flushing, Queens. The mall was raided by the F.B.I. on Feb. 29; that same day, F.B.I. agents also searched two Bronx homes owned by a top Adams administration official, Winnie Greco, who helped organize fund-raisers at the mall for Mr. Adams.

There were also 158 fund-raising events with undisclosed sponsors, including one linked in court filings to ShahidMushtaq, the principal of a construction company in Queens who, along with three associates, pleaded guilty for their role in a straw donor scheme to generate illicit matching funds to Adams’s mayoral campaign.

The questionable donations were cited in a blistering 900-page preliminary audit of Mr. Adams’s 2021 mayoral campaign, as investigators with the Campaign Finance Board chronicled numerous missing payments, sham donations and the potential misallocation of up to $2.3 million in taxpayer money.

The audit, which The New York Times obtained via a Freedom of Information request, is still in draft form, meaning Mr. Adams will get the opportunity to respond and potentially resolve some or all of the board’s red flags.