Mayor de Blasio is meeting today with federal prosecutors and FBI agents investigating whether he doled out favors in exchange for campaign donations, according to reports.

A grand jury has heard evidence in the case, according to unnamed sources speaking to the NY Times, meaning the investigation is near its final stage. Whether or not it will yield criminal charges against de Blasio or members of his administration or campaign remains to be seen.

The questioning is expected to take place in the law office of de Blasio's attorney Barry Berke.

The wide-ranging investigation, one of several state and federal probes, has at various times focused on two businessmen and de Blasio fundraisers implicated in separate instances of alleged corruption involving high-ranking cops, restaurateur Harendra Singh, facing separate corruption charges for alleged bribes of Long Island officials, and lately, a reputed Williamsburg slumlord and the owner of the movie production company Broadway Stages.

The Times reports that the newest targets are Moishe Indig, a rabbi listed among the Village Voice's 10 worst landlords of 2010, and Broadway Stages' Gina Argento. The NY Post reported in December that federal investigators have questioned Indig and other Satmar Hasidic leaders about what City Hall has done in return for their support, and that agents seized one of Indig's cellphones. Around the same time, federal agents arrested Satmar lobbyist and de Blasio fundraiser Isaac Sofer on food stamp fraud charges and, the city tabloids reported, he too was questioned about his relationship with the Mayor's Office.

Earlier this month, the Staten Island Advance reported that the state Comptroller's Office rejected the sale of the old Arthur Kill prison property to Broadway Stages because of the company's involvement in ongoing investigations into de Blasio's fundraising. The paper reported that the $7 million proposed sale price of the land, which is owned by the state, may be as much as $45 million below market value.

Singh is the former owner of the Water's Edge, a now-shuttered restaurant on city-owned property in Long Island City. He was arrested on separate charges as he was negotiating a new contract with the city and owed $1.8 million in unpaid rent and fees. He and associates gave more than $50,000 to de Blasio's campaign, and probers reportedly have looked into whether he used straw donors.

The Times reports that mayoral aides took a keen interest in Singh's contract renewal, repeatedly checking in on the process and eventually taking over the process because they were unsatisfied with how the Department of Citywide Administrative Services was handling it.

Singh is reportedly cooperating with the feds, as is Upper West Side investor and de Blasio donor Jona Rechnitz.

The probe is reportedly separate from investigations into de Blasio's 2014 fundraising for upstate Democratic Senate candidates, and his nonprofit Campaign for One New York, which raised $4.3 million while avoiding campaign finance restrictions. The Manhattan District Attorney's Office has already questioned him in its upstate campaign finance probe.

Earlier this month, following reports that lawyers for de Blasio and his aides could cost taxpayers $11.6 million, de Blasio announced that he plans to start a legal defense fund to alleviate the burden. Such a fund raises its own set of ethical concerns.

The mayor and his spokespeople have maintained throughout the investigations that his fundraising and other actions have been entirely aboveboard.

De Blasio is planning to spend the weekend in Atlanta at the Democratic National Committee meeting, where he will be backing Minnesota Rep. Keith Ellison to become the new DNC chairman.