Undercover FBI agents who saw “Hamilton” with Andrew Gillum will be called to testify in the state ethics case against the former mayor, setting up the possibility of a highly unorthodox court appearance by a key shadowy figure in Tallahassee’s long-running public corruption probe.

If the agents, who posed as out-of-town businessmen named "Mike Miller" and "Mike Sweets," ultimately testify, they could do so over the phone or — if they appear in person — in disguise or behind an identity-blocking screen.

Elizabeth Miller, an advocate who serves as prosecutor for the Florida Commission on Ethics, said in documents filed Friday she intends to call Miller, who posed as a developer, to testify during Gillum’s final hearing. In a witness list filed Monday, she said she also intends to call Sweets, who posed as a medical marijuana entrepreneur.

Back story: Mike Sweets brings medical marijuana link into FBI probe

She asked the judge presiding over the hearing to issue a protective order to keep the agents' real identity secret while allowing Gillum the constitutional right to confront them as a witnesses.

“Based upon the need to protect the agent’s true identity, his safety and the safety of his family, the need to protect the integrity of pending and ongoing undercover investigations, the advocate respectfully submits that there are certain measures the court may and should adopt for the testimony of the agent at deposition and final hearing,” she wrote in her request.

In January, the Florida Commission on Ethics, acting on a citizen complaint, found probable cause Gillum violated civil ethics statutes when he accepted illegal gifts during trips in 2016 to New York City and Costa Rica. During the New York City trip, Gillum took in a performance of “Hamilton” and went on a boat tour around New York Harbor with Mike Miller and others, including his one-time close friend, lobbyist Adam Corey.

Elizabeth Miller wrote that the parties would prefer for the agent to testify over the phone. If he’s required to testify in person, Miller asked that he be allowed to disguise himself or appear behind an opaque screen, with the general public cleared from the courtroom.

She suggested the FBI agent be allowed to testify under his pseudonym, without disclosing his true identity. She also asked that Gillum’s lawyer be barred from asking the agent any question involving any investigation, whether open or closed, or anything about his family, colleagues or others known to be linked to him. Gillum’s attorney, Barry Richard, does not oppose the request.

Mike Miller back story:

Mike Miller was among several undercover FBI agents who arrived in Tallahassee in the summer of 2015 to investigate allegations of public corruption. They hobnobbed with local officials, working their way into some of their inner circles, before disappearing in 2017 just before the undercover probe burst into public view.

The federal investigation, which appears to be ongoing, led in December to the indictments of Gillum’s former colleague, suspended City Commissioner Scott Maddox, and former Downtown Improvement Authority Executive Director Paige Carter-Smith on bribery and other federal charges.

Gillum, who narrowly lost the governor’s race last year amid late campaign revelations involving the trips, has long said the FBI told him he was not a target of its probe. The bureau, however, has never confirmed that. Gillum, who recently launched a major statewide Democratic voter registration drive, has also denied wrongdoing in the state ethics case.

A final hearing in the Gillum case had been set for April 24-26, with Administrative Law Judge E. Gary Early presiding. However, Miller, the Ethics Commission advocate, asked for a postponement because of issues involving Corey and his lawyer, Chris Kise, who has had recent health issues.

Miller wrote that late last month, Kise’s law firm advised that he had been hospitalized in Tampa for a cardiac problem and it was unclear when he would return to Tallahassee. The firm asked that Gillum’s hearing be postponed until August.

In her request for a delay, Miller said neither the commission nor Gillum’s lawyers have been able to find Corey, who is also a central figure in the FBI probe.

Miller served a subpoena on Corey through Kise, she wrote in her filing. But Kise advised he was not authorized to accept service on behalf of Corey and has not provided an address where Corey can be served.

Corey declined to testify before Ethics Commission staff last year because of the FBI investigation. However, he provided an affidavit saying Gillum never paid for a villa stay in Costa Rica and that Mike Miller paid for the outings in New York.

Kise signaled to Ethics Commission staff before he became ill that Corey would be available to testify during a deposition and the final hearing, according to Miller's filing.

“Adam Corey’s witness testimony is critical to the Commission on Ethic’s ability to prove the elements of the violations in this case,” she said. “No other witness can give testimony regarding the Costa Rica trip that will be as effective as Adam Corey’s live explanation to the court.”

Miller wrote she plans to call nearly two dozen witnesses, including Gillum’s wife, R. Jai Gillum, and his political confidante, lobbyist and lawyer Sean Pittman, both of whom were on the Costa Rica trip. She also plans to call an employee at the downtown NYC hotel where Gillum stayed. Gillum has said he stayed in his brother’s room, but Miller noted that the witness will testify one of the rooms was reserved in the mayor’s name.

Gillum’s attorney, Barry Richard of Tallahassee, doesn't oppose the state’s motion for secrecy involving the FBI agents’ testimony. However, he filed a document Monday opposing postponement of the hearing.

Richard wrote that the Ethics Commission’s advocate can’t give any assurance that he will be available to testify in August. And even if he is subpoenaed, Richard said there is no reason to believe he won’t assert his Fifth Amendment rights and refuse to testify.

“It is clear that Mr. Corey does not want to testify in this case,” Richard wrote. “He has steadfastly refused to cooperate with either counsel and has kept himself beyond the subpoena power of this court.”

Contact Jeff Burlew at jburlew@tallahassee.com or follow @JeffBurlew on Twitter.