A federal corruption probe into NYPD officials taking gifts from two businessmen in return for favors has spread to whether fundraisers for Mayor Bill de Blasio illegally raised funds for his campaigns or for his Campaign for One New York, according to sources familiar with the investigation.

Nobody has been charged in the probe, which is described as in its preliminary stages, the sources said.

The sources noted that it is not unusual for the Justice Department and the FBI investigating political fundraising to end up charging individual fundraisers or contributors rather than candidates.

That happened most recently in Democrat Hillary Clinton’s 2008 presidential race, the 2012 New York U.S. Senate campaign of Republican Wendy Long and the 2013 New York City mayoral campaign of Democrat John Liu. The candidates themselves were not accused of any illegal activities.

The businessmen in the de Blasio investigation, Jona Rechnitz and Jeremy Reichberg, first came to investigators’ attention as an outgrowth of a separate probe into police brass being paid with cash, jewelry, tickets to sporting events and travel. In return, the brass were expected to provide protection for businesses and the assurance of extra policing in Brooklyn’s Borough Park section for community happenings, including street events during Jewish holidays, according to sources.

WCBS-TV first reported the de Blasio investigation Friday night.

advertisement | advertise on newsday

The businessmen have not been charged. Rechnitz’s lawyer, Marc Harris, declined to comment Saturday; a lawyer for Reichberg could not be reached.

Sources familiar with Rechnitz said he believes he has done nothing wrong in contributing to de Blasio’s campaigns and is upset that his name has been featured prominently in news reports.

Rechnitz, owner of JSR Capital LLC, a real estate investment, development and management company that owns buildings in Manhattan and Brooklyn, raised about $50,000 for de Blasio, while he and his wife each contributed the maximum allowed — $4,950 — to his 2013 campaign, according to public records.

Rechnitz and Reichberg were on a committee that planned de Blasio’s 2014 inaugural party. Reichberg also hosted a fundraiser in 2014 for One New York, a de Blasio nonprofit designed to support progressive causes.

De Blasio began closing down the group last month after it was bashed by watchdog groups as a “shadow government” of lobbyists at City Hall.

Get the Newsday Now newsletter!

The best of Newsday every day in your inbox.

While it was not immediately clear what aspects of de Blasio’s fundraising is under examination or how it relates to the two businessmen, de Blasio’s campaign has said it will return the $9,900 in campaign contributions to Rechnitz and his wife.

“We are fully confident that the campaign has conducted itself legally and appropriately at all times,” campaign spokesman Dan Levitan said Saturday in a statement.

De Blasio did not comment directly on the developments.

The overall investigation has a number of different branches that for the moment, at least, seem to center on Rechnitz and Reichberg. To date, four senior NYPD officials — including three deputy chiefs and a deputy inspector — reassigned to desk duties as a result of the investigation.

There are also investigations into the use of funds from the city correction officers union to invest in a hedge fund in return for payoffs, and an alleged Ponzi scheme supposedly involving the sale of liquor to restaurants, sources said.

advertisement | advertise on newsday

With Matthew Chayes