(CNN) An ongoing federal investigation into public corruption in Tallahassee, Florida, 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."

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