Federal prosecutors are expected to rest their case in chief Friday in the perjury trial of Tim Mapes, the former chief of staff to Democratic Illinois House Speaker Michael Madigan accused of lying to a federal grand jury investigating his boss.

Mapes, 68, of Springfield, is charged with perjury and attempted obstruction of justice, accused in an indictment of lying in answers to seven questions during his grand jury appearance more than two years ago.

Prosecutors have so far presented 15 witnesses and dozens of wiretapped phone conversations, emails, and other documents in an effort to prove that Mapes was lying when he said he was unaware that Madigan’s longtime confidant, Michael McClain, was doing sensitive “assignments” for the speaker even after retiring from lobbying in 2016.

The prosecution’s case has also included the audio of Mapes’ entire March 31, 2021, testimony before the grand jury, offering a rare glimpse into a secretive process and illuminating how big-time political corruption investigations play out behind the scenes.

Mapes, who served for more than 25 years as Madigan’s chief of staff as well as stints as executive director of the state Democratic Party and the clerk of the House, faces up to 20 years in prison on the most serious counts of the indictment.

Mapes has denied making any false statements, and his attorneys have argued that he did his “level best” to provide truthful answers. They also accused prosecutors of asking open-ended questions and failing to provide Mapes with any corroborating materials that might refresh his recollection of years-old conversations.

The defense is expected to begin presenting its case on Monday, and will call an expert witness who will testify on the faults of human memory. Mapes has not said whether he will testify, though it’s considered a long shot given his previous track record and the general risks involved.

While the charges against Mapes are fairly straightforward, the trial has been anything but ordinary, especially given the backdrop of the political corruption scandal that roiled Illinois politics and helped end Madigan’s record, decades-long run as speaker.

A slew of Democratic Springfield insiders have lined up to testify for the prosecution, including state Rep. Bob Rita, ex-legislators Lou Lang and Greg Harris, and former top aides to Madigan such as Tom Cullen, Will Cousineau, and Craig Willert.

[ Former top Michael Madigan aide on trial: What you need to know — and what’s next for Tim Mapes ]

On Thursday, the testimony of Republican lobbyist Nancy Kimme added a new political dimension to Mapes’ trial and illustrated how Illinois party labels often don’t matter when it comes to cutting a deal.

Kimme, who served as chief of staff to Comptroller Judy Baar Topinka, a Republican, testified about her involvement in a plan to transfer a state-owned parcel of land in Chinatown that is also at the heart of the racketeering charges against Madigan himself.

Kimme testified that McClain first reached out to her about the Chinatown project in late 2017, and that she later met at then-25th Ward Ald. Daniel Solis’ West Side office with McClain, Solis and the developers seeking to turn a parking lot into a hotel complex.

Unbeknownst to all involved, Solis was cooperating with the government at the time, and secretly recorded Madigan as he allegedly solicited business for his private property tax law firm during the discussions about the parcel with the hotel developers.

Lang, meanwhile, testified Thursday for the second time about that painful end to his 32-year legislative career.

[ Tim Mapes perjury trial: Evidence seen and heard by the jury ]

Prosecutors played a series of calls from May 2018 where Mapes and McClain discussed Lang’s future after a medical marijuana advocate accused him of sexual harassment at the end of the spring 2018 legislative session.

Lang was hoping to stay in the House and get back the leadership position he’d given up the day of the accusations. He called for a legislative inspector general investigation, which determined the allegations to be unfounded but noted that the accuser, Maryann Loncar, had refused to participate in the examination.

“Let me put you on with the boss. OK?” Mapes told McClain in one call. “So you’re going to inform him what you know and go from there.”

Prosecutors alleged the episode demonstrates “as clear as day” that Mapes knew McClain communicated with Madigan in 2018, because “Mapes sets up that conversation.”

Lang declared himself vindicated from the initial allegations, but later in 2018, Madigan and McClain had heard of another potential #MeToo allegation that might surface, prompting Madigan to tell McClain to let Lang know he should give up the seat he held for decades.

In the grand jury, Mapes was asked repeatedly whether he was aware of McClain having any contact with Lang after McClain retired from lobbying in 2016.

“I’m not aware of any,” Mapes said.

You don’t recall any conversations with either of them about them talking to each other about it? he was asked.

“That’s correct,” Mapes said.

But numerous wiretapped recordings played for the jury Thursday show the two men spoke many times about it,.

In one call from Oct. 26, 2018, McClain told Mapes, “My assignment is to tell Lou Lang that he has no life in the House anymore.”

“You’ve had one discussion with him. Did you have more?” Mapes asked.

“I’m doing it in tiers,” McClain responded.

In a recorded telephone call from Oct. 31, 2018, McClain said he would wait until fundraising checks that they had directed Lang to disperse to other Democratic candidates cleared, “Then I gotta tell (Lang) he’s gotta move on, he has no future in the House.”

On the witness stand Thursday, Lang calmly told prosecutors that he was not surprised that it was McClain who called him to deliver the news because “he was the message sender.”

“Mr. McClain was the person dispatched to tell members things that the speaker didn’t want to tell them,” Lang testified.

In the grand jury, Mapes was asked repeatedly whether he was aware of McClain having any contact with Lang after McClain retired from lobbying in 2016.

“I’m not aware of any,” Mapes said.

You don’t recall any conversations with either of them about them talking to each other about it? he was asked.

“That’s correct,” Mapes said.

jmeisner@chicagotribune.com

rlong@chicagotribune.com