Follow CBSMIAMI.COM: Facebook | Twitter

MIAMI (CBSMiami/CNN) — An ongoing federal investigation into public corruption in Tallahassee, threatens to damage the nascent campaign of Democratic gubernatorial nominee Andrew Gillum, the city’s mayor.

The FBI investigation into whether out-of-town developers were able to influence city development projects has already become fodder for political attacks against the gubernatorial candidate, who won the state’s Democratic primary last week and rose to national prominence because of his historic win and gripping personal story.

“He is embroiled in a lot of corruption scandals,” Rep. Ron DeSantis, Gillum’s Republican opponent, said on Fox News after the primary win. “This guy can’t even run the city of Tallahassee. There is no way Florida voters can entrust him with our entire state.”

Gillum’s level of exposure in the probe remains unclear, though the mayor has long said publicly that the FBI told him he was not a focus of the investigation. His campaign officials have said the same thing and looked to turn the attack back on DeSantis.

“Mayor Gillum is not a subject of the FBI investigation, and he’s committed to rooting out any corruption or wrongdoing in Tallahassee,” said Geoff Burgan, Gillum’s spokesman. “We’re not going to take ethics lectures from Congressman Ron DeSantis, who is marching in lockstep with the most morally, ethically and legally challenged President in American history.”

The FBI declined to comment on the investigation.

Gillum has not been named in any of the subpoenas, but questions have been raised about his potential involvement, in part because the investigators have compelled information from Adam Corey, a lobbyist and longtime Gillum friend who volunteered as finance chair on his 2014 mayoral campaign. Hundreds of Corey’s emails have been posted online, at Gillum’s direction, fodder for Republican groups that will spend millions looking to stop Gillum’s campaign.

Gillum’s ties to Corey, whom he met while he was in college, have long raised questions. The Tallahassee Democrat reported in 2015 that Gillum’s 2013 decision as a city commissioner to vote to fund a multimillion-dollar project tied to Corey through the city’s community redevelopment agency raised questions because of their friendship, even though city lawyers deemed Gillum did not have a conflict of interest.

The vote made way for Corey and other partners to convert a turn-of-the-century electric plant into an upmarket restaurant named Edison.

Those questions grew when the paper reported on Gillum and Corey vacationing together in Costa Rica, where they agreed to meet with Mike Miller, a name used by one of three FBI agents posing as developers, once they were back in Florida. Gillum’s chief of staff told the paper that the trip was not business related and that he was on vacation with friends. Questions have also been raised about a 2016 trip to New York, where Corey and Miller were also present. A local television station published a photo in August of 2017 that showed Corey, Gillum and an FBI agent sitting in the back of a boat in New York harbor with the Statue of Liberty in the background.

According to public documents, the undercover agents posing as developers got close to city officials and lobbyists in an attempt to snuff out public corruption. FBI agents subpoenaed thousands of records in June 2017 and Gillum’s office then posted those records online. Reporting from the Tallahassee Democrat found that a cadre of city officials and power brokers have been named in the subpoenas, but Gillum’s campaign has denied any connection to the probe and pledged to work with the FBI.

Even so, Republicans will seek to use the investigation to bludgeon Gillum’s campaign. The Republican Governors Association has already put out a digital ad on the probe and Jon Thompson, a spokesman for the group, told CNN that is likely just the beginning.

“This FBI investigation will haunt Andrew Gillum’s gubernatorial campaign and will be a very lethal attack,” he said.

Jared Leopold, spokesman for the Democratic Governors Association, responded, “Ron DeSantis has spent his political career pandering to far-right fringe elements, by voting to raise the retirement age and jack up health care costs on Floridians with pre-existing conditions. The RGA is desperate to rewrite history now that they’re saddled with a candidate who is more extreme than Trump.”

The Gillum-DeSantis race is likely to be one of the most expensive gubernatorial contests in the country, with both campaigns and outside groups spending millions to control Florida’s executive branch.

Gillum has sought to fight back on the attacks by distancing himself from Corey and pledging to be helpful, while also using his approach to the investigation to attack President Donald Trump, a vocal DeSantis backer.

“We want to make sure that any individual that participated in that is held fully accountable. The good news is, is that it doesn’t involve my government or myself. We have all been fully cooperating,” Gillum told CNN on Sunday.

Despite their longtime friendship, Gillum also distanced himself from Corey by referring to him as just a campaign volunteer.

Referring to Trump’s constant attacks against the FBI for the ongoing investigation into Russian interference in the 2016 election, Gillum added, “The difference between how we have addressed this and how Ron DeSantis and Donald Trump have addressed the FBI is that we have welcomed them and have tried to aid in their work.”

No charges have been filed to date as a result of the Tallahassee probe.

(© Copyright 2018 CBS Broadcasting Inc. Cable News Network, Inc., a Time Warner Company, contributed to this report).