CHICAGO (AP) — A federal judge in Chicago sentenced a former chief of staff to longtime Illinois House Speaker Michael Madigan to two and a half years in prison Monday for lying under oath to a grand jury to protect his once-powerful boss.

U.S. District Judge John F. Kness imposed the sentence on Timothy Mapes, 69, of Springfield. A jury in U.S. District Court in Chicago last year convicted Mapes of making false declarations before a grand jury and attempted obstruction of justice.

“I don’t understand why. You were immunized by the grand jury, and all you had to do was go in and tell the truth,” Judge John Kness said. “You knew the testimony was false. ... I can’t ignore that finding.”

Mapes is to report to prison in mid-June to begin his sentence, the judge said.

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Kness said in court he felt a sense of loyalty had potentially motivated Mapes’ deception, but said that such a feeling was a mistake.

“Your loyalty was misguided, and now you will pay the price for that,” he said.

Prosecutors told jurors that Mapes lied repeatedly when he testified in 2021 to a grand jury investigating Madigan and others. They said he specifically lied when he said he couldn’t recall any relevant details about Madigan’s ties to Michael McClain, who was a Madigan confidant.

One witness, a legislator, told jurors that Madigan, Mapes and McClain formed a mighty triumvirate — with Madigan at its head — in the Illinois House for years, controlling which bills got through the legislative body.

Government evidence included wiretapped phone recordings and audio of Mapes testifying before the grand jury.

“He did everything he could to obstruct the process … to minimize his participation, to act as if he was clueless,” prosecutor Julia Schwartz said of Mapes during closing arguments.

During his closings, defense attorney Andrew Porter said Mapes would have had no motivation to lie to protect his old boss after Madigan had forced him to resign in 2018 amid allegations of harassment, which Mapes denied.

“Why would he fall on his sword for a guy who kicked him to the curb three years before?” Porter asked.

Federal jurors last May convicted four defendants of bribery conspiracy involving the state’s largest electric utility. Prosecutors said McClain, two former ComEd executives and a former utility consultant arranged contracts, jobs and money for Madigan’s associates to ensure proposed bills boosting ComEd profits became law.

A year before Madigan was indicted and amid speculation that he was a federal target, Madigan resigned from the Legislature as the longest-serving state House speaker in modern U.S. history.

The indictment accused Madigan of reaping the benefits of private legal work that was illegally steered to his law firm, among other things. He has denied any wrongdoing.

Madigan lost the speakership and resigned his House seat in 2021, a year before being indicted along with McClain in a separate racketeering case alleging Madigan sold his office for personal gain. That trial is set to begin in October.