Former ComEd executive Fidel Marquez, who wore a wire for the FBI against his friends and colleagues in 2019, took the witness stand Tuesday afternoon for what is likely to be days of testimony in the trial of former Illinois House Speaker Michael J. Madigan.Marquez is one of two key cooperators in the racketeering conspiracy case against Madigan and his longtime ally, Michael McClain. His recordings and testimony formed the backbone of last year’s ComEd bribery trial, in which McClain and three others were convicted.FBI agents confronted Marquez at his mother’s home around 6 a.m. on Jan. 16, 2019. They ultimately took him in their car to a strip mall parking lot when people in the home began to stir, and they convinced him to make the secret recordings after playing some of their own.Marquez then spent four months recording McClain, as well as former ComEd CEO Anne Pramaggiore, ex-ComEd lobbyist John Hooker and then-City Club President Jay Doherty — the three people convicted along with McClain.Marquez spent a week on the witness stand during their trial, an experience that ended with a fiery cross-examination by McClain defense attorney Patrick Cotter, who continues to represent McClain in the latest case.“You decided to become their worker,” Cotter demanded of Marquez in March 2023, in a reference to the FBI. “And make calls when they wanted to make calls, and go to meetings and tell lies they wanted you to tell.”The other key cooperator in this trial is former Chicago Ald. Danny Solis (25th), who wore a wire against Madigan and other powerful politicians in hopes of avoiding prison. Solis is not expected to take the stand until later in the trial, when prosecutors begin laying out evidence of schemes involving Madigan's law firm.Meanwhile, Marquez is likely to revisit much of his testimony from last year’s case about an alleged bribery conspiracy at ComEd. He took the stand around noon Tuesday, after a later than usual start to the trial day. U.S. District Judge John Blakey gave the jury an extra two hours to vote in the morning.The judge appeared on the bench with an “I Voted” sticker on his robe. At least two jurors could also be seen wearing their own “I Voted” stickers, and at one point Madigan defense attorney Tom Breen waved his around the courtroom.Marquez testified for about 15 minutes before Blakey sent the jurors off for lunch. He’s expected to resume his testimony when that break is done.Assistant U.S. Attorney Amarjeet Bhachu jumped right into Marquez’s legal troubles as he began his direct examination.Jurors heard that Marquez was charged with a bribery conspiracy in 2020, pleaded guilty but has yet to be sentenced. He explained how he agreed to cooperate, and that prosecutors are expected to recommend no prison time for him as a result of his assistance.Marquez told the jury that he recorded McClain, Pramaggiore, Hooker and Doherty — not Madigan.Bhachu also revisited an incident earlier this year in which Marquez gave a false answer on a form while trying to buy a gun. Prosecutors say he answered “no” when the form asked if he was “under indictment or information in any court for a felony.” He also allegedly answered “no” when asked if he had “ever been convicted in any court … of a felony.”Prosecutors in 2020 filed their charges against Marquez using a document known as an “information," not through an indictment.Marquez told the jury Tuesday that the incident with the form “was a mistake,” and not deliberate.He also said he tried to buy the gun to fend off rattlesnakes — the same explanation that was given earlier this year to U.S. District Judge Mary Rowland, who presides over Marquez’s criminal case.Rowland lectured Marquez about the incident last April, telling him he’d “just given a really beautiful piece of ammunition to Madigan’s lawyer.”