Defense attorneys for former New Roads Mayor Tommy Nelson have subpoenaed a disgraced former FBI agent for testimony in the final week of Nelson’s racketeering and wire fraud trial in Baton Rouge federal court.

Darin Lee McAllister, 45, was one of three undercover federal agents who worked on the two-year investigation that led to Nelson’s indictment.

But McAllister was convicted in December in Nashville on 15 counts of wire fraud and three counts of making false oaths in a bankruptcy case not related to Nelson’s indictment. A jury concluded that McAllister’s wire frauds involved bank funds totaling $1.2 million.

While McAllister was under investigation in Tennessee, he was working undercover in Louisiana on the Nelson investigation.

“I can’t really comment,” Page A. Pate, one of Nelson’s attorneys, said Friday in an e-mail. “I can only confirm that we subpoenaed him (McAllister) after the court’s ruling on the admissibility of his federal criminal conviction.”

Chief U.S. District Judge Ralph E. Tyson ruled last month that McAllister’s felony conviction could not be revealed to the jury unless the former federal agent testifies.

Prosecutors told the judge they would not call McAllister to the witness stand.

But Pate, an Atlanta attorney, said last month he would seek permission to reveal the conviction if something unexpected happened at trial.

The unexpected move is that Nelson’s defense team subpoenaed McAllister as a defense witness.

Prosecutors in the Nelson case declined to comment Friday.

“We can’t comment on it one way or the other while we’re in the middle of this trial,” First Assistant U.S. Attorney Walt Green said.

McAllister had been scheduled for sentencing Thursday in Nashville, but his attorney won a postponement until July 21.

Travis Hawkins, McAllister’s Tennessee attorney, told Senior U.S. District Judge John T. Nixon in Nashville that the former FBI agent had been subpoenaed for testimony in Nelson’s Baton Rouge trial.

Nelson’s trial opened June 6 and is scheduled to continue through Thursday. Testimony is scheduled to resume Monday morning.

The former mayor lost his bid for re-election last year after he was indicted on charges of racketeering, wire fraud, use of telephones in aid of racketeering and lying to FBI agents.

Nelson is alleged in the indictment to have accepted more than $22,000 in bribes from undercover agents posing as corrupt officials of a garbage can-cleaning business known as Cifer 5000.

The alleged bribes were paid in return for Nelson’s pledge to help Cifer obtain municipal business in New Roads.

And jurors have viewed and listened to recordings of Nelson’s conversations with the undercover agents.

But Pate and co-counsel, Michael A. Fiser, of Baton Rouge, told Tyson before trial that they may argue for dismissal of all charges. The two Nelson attorneys told the judge that FBI agents and a government-paid undercover operative may have induced the then-mayor to do things he otherwise would not have done.

FBI agents have testified that they did not do anything improper during their investigation of Nelson.

Cifer 5000 was an imaginary company used in an FBI sting known as Operation Blighted Officials.

In addition to Nelson, the three-year operation also resulted in indictments against six other municipal officials in Port Allen, St. Gabriel and White Castle.

Assistant U.S. Attorneys M. Patricia Jones, Michael J. Jefferson and Corey R. Amundson have not yet rested their case against Nelson.