Tallahassee Mayor Andrew Gillum shocked the Florida establishment on Tuesday, winning the state’s Democratic nomination for governor. The Bernie Sanders–backed progressive ran left while the rest of the primary field—including a moderate front-runner with deep ties to the state and a self-funding, self-proclaimed “radical centrist”—camped out in the center. Gillum’s win made him the left’s latest breakout star of the midterms, joining the likes of New York’s Alexandria Ocasio-Cortez and Georgia’s Stacey Abrams.

Much of the mainstream coverage of Gillum’s historic victory, though, includes a passing reference to a potential blemish on his political résumé: an ongoing public corruption case involving his home town, a city he has led since 2014. As the Washington Post put it, “Gillum has faced questions about an FBI investigation that appears to be focused on Tallahassee city government.” The New York Times, likewise, nodded at the potential scandal in its main story without going into detail. Gillum struggled to raise money early in his campaign, the paper notes, “as donors worried about an FBI investigation into City Hall corruption.”

Those vague references raise more questions than they answer. Here’s what we know—and what we don’t.

Why are national news outlets so mealy-mouthed about this case?

Because no one really knows what’s going on. The FBI doesn’t talk about ongoing investigations, and the agency has yet to file charges against anyone. The vast majority of what we do know comes by way of shoe-leather reporting by local news outlets like the Tallahassee Democrat, which suggests the feds are looking into local land deals and other government business they believe to be shady. But the full size of the investigation is unknown, as are all the targets.

For his part, Gillum says he met with the FBI and that the agency has assured him that he is not the focus of its investigation, and he has promised his full cooperation. “While no one likes the city being under the FBI’s full scrutiny, in light of what is happening nationally, we must remember that the FBI is here to protect us and we must aid them in their work,” he said in June. He’s offered similar comments since winning the primary. “I welcome their investigation to get to the bottom of any corruption that might exist,” he told Fox News on Wednesday.

Back up. How’d this whole thing start?

According to the Tallahassee newspaper, three undercover FBI agents showed up in Tallahassee back in 2015, posing as out-of-town developers interested in pursuing opportunities in the state capital. The agents then spent the next year hobnobbing with local business leaders and cozying up to local officials before disappearing in early 2017. That summer, the FBI delivered subpoenas to the city government requesting thousands of pages of documents dating back to 2012. More subpoenas soon followed, as did the apparently accidental unsealing of a search warrant targeting a city commissioner and his long-time business associate. While it’s impossible to say how far along the investigation is today, judging by the number of local businessmen spotted last month going in and out of a local federal courtroom with their white-collar attorneys in tow, indictments could be on the horizon.

So where does Gillum fit into all this?

Gillum was elected mayor in 2014 and has held city office since 2003, when at 23 he became the youngest person ever to win a seat on the Tallahassee City Commission. Spending a decade and a half in local government means crossing paths with a wide array of movers and shakers, all with their own interests and any of whom could, theoretically, be caught up in the probe. But Gillum’s most direct connection to this case is through a local businessman and lobbyist, Adam Corey, who appears to have introduced the FBI agents to a number of key players in the city, including Gillum. It’s unclear whether Corey believed the agents were developers when he made the introductions or if he was knowingly working with these undercover feds.

Gillum and Corey have known each other since their college days, and Corey served as Gillum’s treasurer during his 2014 mayoral campaign. In 2016, Corey reportedly set up a meeting at his Tallahassee restaurant between Gillum and the FBI agents (whom Gillum believed were developers). According to an email obtained by the Tallahassee Democrat, Corey sent a calendar invite for that meeting while he and Gillum were at an exclusive, $1,400-a-night luxury resort in Costa Rica. Gillum says it was a personal trip in which no business was discussed, but ethics watchdogs remain unconvinced.

Got it. Anything else?

Corey also arranged a weekend meet up later that year in New York City, where he, Gillum, and at least two of the FBI agents took a boat ride and may or may not have attended a Mets game and seen Hamilton. Gillum, who was already in New York City finishing up business for a liberal nonprofit, was photographed on the boat with one of the agents, who went by the name Mike Miller. That trip remains the subject of a state ethics probe. Gillum has declined to state publicly whether he attended the baseball game or Broadway play, which were mentioned in Corey’s digital invite to the group, but the mayor maintains that he paid his own way during the festivities and that the trip was “merely friends getting together” off the clock. “I have known Adam for 20 years and I had spent time with Mike who was, over the almost year that I knew him, someone who portrayed himself as a developer interested in investing in [Tallahassee’s] south side,” Gillum said in a statement last year. “No public money was used and no city business was discussed on the trip.”

Those seem like not-so-great optics.

True, it’s never good to find yourself mentioned in the same breath as the words FBI investigation when you’re running for office. But meeting socially with potential developers, as Gillum says he believed he was doing, isn’t illegal or even out of the ordinary for a mayor hoping to drum up new business for his city. The fact he agreed to the outings, by itself, tells us little about potential wrongdoing. The big question is whether any illicit deals or favor trading took place, and no one has publicly accused Gillum of any such thing.

He maintains he took the meetings as a courtesy to Corey and now feels taken advantage of. “I had a trusting relationship and I felt like I allowed people around me who were acquaintances of his because I trusted him,” Gillum told the Democrat in January after the newspaper obtained the boat photo. “And it appears that if these guys were here for an investigation, that the only way they got to me was by leveraging my friendship with Adam.”

Did any of this come up in the primary?

Not really. Gillum’s opponents largely ignored it, though one reason for that may be because he looked like a long shot for most of the campaign. Heading into Tuesday, Gillum was sitting in a distant fourth place in RealClearPolitics’ rolling average of polls with less than half the support of the front-runner, former congresswoman Gwen Graham.

Will it come up in the general?

It already has. Gillum’s GOP opponent in the general election, Trump-backed U.S. Rep. Ron DeSantis, made sure to emphasize the investigation during a Fox News appearance on Wednesday. “He is embroiled in a lot of corruption scandals,” DeSantis said of his opponent without providing specifics. “This guy can’t even run the city of Tallahassee. There is no way Florida voters can entrust him with our entire state.”

DeSantis wouldn’t possibly associate himself with anyone plagued by scandal, right?

Um…