The ride around the Statue of Liberty looked harmless enough.

Andrew Gillum, then just a city mayor with high aspirations, hopped aboard a small boat in New York harbor on a Friday morning in August, 2016.

"It was merely friends getting together to sightsee," Gillum said of the short trip a year later.

But former federal agents and prosecutors say the outing provides an important glimpse into public corruption in Tallahassee, and the lengths to which undercover agents went to investigate Gillum.

Evidence shows that the boat trip and other events in New York were organized by undercover agents. Indeed, two agents were on the boat, unbeknownst to Gillum.

And if FBI agents organized the outing, it implies that their interest in Gillum had evolved into a "predicated" investigation, former agents told the Times/Herald. It would require the agents working the case to show their bosses that they have allegations or facts about criminal wrongdoing that would justify having Gillum aboard.

The boat trip would also have likely involved Justice Department officials in Washington, agents say.

"Whoever was invited (on that boat), that list is short, and it's reviewed a number of times," said former FBI agent James Wedick, who worked on many public corruption investigations over 34 years at the bureau. "We're not going to let anybody on that boat that we don't think is worthy of a criminal investigation, if we can help it."

The reason for such scrutiny? To prevent an investigation from leaking out and unfairly tarnishing a politician's reputation.

That may be exactly what happened to Gillum, however, after photos of his boat trip sitting next to an undercover agent and a lobbyist surfaced last year.

The FBI probe has already become an issue in his race to become the state's next governor. His Republican opponent, former Congressman Ron DeSantis, has said Gillum is "embroiled in a lot of corruption scandals."

And pictures of him on the boat are almost certain to flood Floridians' mailboxes and television sets as Gillum hopes to make history by becoming Florida's first black governor.

Gillum has not been charged with a crime and has said that FBI agents assured him he's not a target nor a focus of the investigation. Outside of the boat trip, nothing has publicly surfaced that implies the FBI suspected him of wrongdoing. The FBI has not commented on the investigation.

Barry Richard, an attorney representing Gillum in a state ethics investigation into the New York trip, wasn't there when Gillum met with FBI agents at his home in June last year. But he said nothing Gillum has described implies he's done anything illegal.

"People are trying so hard to find some connecting dots," Richard said. "But nobody's ever found any evidence connecting any dots to these things."

Former agents and prosecutors cautioned against drawing a conclusion about Gillum's boat trip.

Liam Brennan, who led Connecticut's Public Corruption Task Force for two years before leaving in March, said it was not uncommon to have predicated investigations lead nowhere.

"The Department (of Justice) and the Bureau get tips all the time," Brennan said. "You want your investigators to poke around and see how high up corruption goes."

What triggered the FBI to start digging into Tallahassee corruption is unknown.

But agents ran a typical playbook for ferreting out public corruption, even using the same undercover agent that helped bring down a California state senator.

Their case began as early as August 2015, when "Mike Miller," an undercover agent posing as a Nashville developer, was first spotted hobnobbing at a Tallahassee Chamber of Commerce event.

From there, agents began making the rounds, talking to city and county officials and politicians and pitching development plans for their made-up businesses.

In addition to Miller, there was Mike Sweets, who was posing as a medical marijuana businessman from Arizona, and Brian Butler, who supposedly owned an energy consulting business in Atlanta. All three names are believed to have been pseudonyms.

Their conduit into Tallahassee's political class appears to have been lobbyist Adam Corey, a longtime friend of Gillum's and his campaign treasurer in 2014. Corey helped the agents set up meetings with city and county officials. The agents inserted themselves into the social scene, even working out at Gillum's gym.

Corey introduced Gillum to Miller and Butler over drinks at a restaurant in May 2016.

That meeting, and the meetings with city and county officials, might not have required additional scrutiny by Justice Department officials, according to the former agents.

But when Corey invited Gillum to hang out with the agents in New York City three months later, it indicated a significant step up in the investigation, former agents said.

Gillum went to New York to attend a conference that week for his side job working for a non-profit. On the last night of the trip, he stayed with his brother at a Manhattan hotel, and the next day, went with his brother, Corey, Miller and Sweets on the boat ride.

Public corruption investigations, where agents dangle goodies to entice politicians they encounter, are not supposed to cast wide nets, according to Joseph Lewis, who retired in 2004 after 27 years with the FBI, nine of those years overseeing public corruption cases in Chicago.

The investigations are supposed to be focused. And when Gillum went to New York and met the undercover agents, they likely would have needed a significant reason to believe that something incriminating might happen, Lewis said.

"You can't just set something up and run it at them willy-nilly," Lewis said. "You're destroying someone's reputation."

Some clues lend credence to the idea that the boat ride was a setup by the FBI. For one, Miller planned the outing, according to a calendar invitation Corey sent Gillum before the trip.

"Gents, here is the plan from Mike Miller: We are going to do the Mets game Wednesday night," Corey wrote in the calendar invite. "My buddy arranged another boat deal for us Thursday afternoon. Also, we have rooms arranged for everyone starting Wednesday night at the Millennial (sic) Hilton."

In addition, Gillum told the Tallahassee Democrat in January that either Miller or Sweets told him that the boat belonged to a buddy of theirs. And one of the FBI agents involved in the investigation appeared to have disclosed details on the case to the Florida Bar last year, saying that he had overseen a large investigation in Florida with a half-million dollar budget and multiple covert vehicles.

Undercover agents will use boats and other craft to maintain a persona. In 2008, for example, an undercover agent looking into corruption in Broward County used a large yacht to entertain a slew of county politicians.

The events on that yacht were under surveillance, it turned out, and it's likely that if the boat used to ferry Gillum belonged to the FBI, he was under surveillance, too, according to former agents.

But since that New York boat trip, the probe appears to have shifted away from him. Subpoenas served on Tallahassee City Hall have not named Gillum. He's not had any other meetings with FBI agents.

A federal grand jury in Tallahassee has called in several witnesses, according to the Tallahassee Democrat. One of those people was Tallahassee's  former city manager. His lawyer said that the grand jury did not ask the city manager about the mayor.

Former agents said that investigators might have naturally taken special interest in Gillum simply because he was the biggest fish in the small pond of Tallahassee politics.

Former FBI agent Jeff Danik, who worked corruption cases in Miami and West Palm Beach before leaving in 2015 called Gillum's situation "unfair."

"Handing an opponent something like this to exploit is patently unfair," Danik said. "It's a lack of leadership, and at this point the FBI and DOJ don't have any good options to unwind their damage."

Gillum was obviously a person of interest, otherwise they wouldn't have taken the time to meet with him, said former Assistant U.S. Attorney David Moyé, who has closely followed the reporting on the FBI's Tallahassee probe. "(But) I think he's being correct when he says, 'I'm being told I'm not a target of the investigation.' That's probably accurate."

Times/Herald staff writer Elizabeth Koh contributed to this report.