He slouches restlessly, waiting to speak about the ghosts of his past to college students who have gathered to watch a documentary about police brutality.
When the film is over, Aaron Patterson comes forward to offer a personal epilogue.
In some ways, it should be a happy one.
Instead of counting the days on death row from a 6-by-9 cell, Patterson is a free man -- thanks to an extraordinary gubernatorial pardon that declared him a victim of a "manifest injustice."
But on this day at the University of Chicago, Patterson is not in a forgiving mood.
He's thinking about his 17 years behind bars, most on death row, despite repeated claims of innocence and accusations of police torture that won him international support.
"None of these cats -- the mayor, the superintendent of police, the Cook County state's attorney -- will get any sleep on this watch unless they say they made a mistake," he vows, his voice rising, his eyes flashing.
Nearly a year after he walked out of prison as part of a dramatic emptying of Illinois' death row, Aaron Patterson refuses to fade away or forget.
In the months since, he has crisscrossed the city as if it were a giant prison cell, popping up at rallies, schools, protest marches -- anyplace he can to talk about other people's injustices or his own.
Although he is free to navigate a world that he could only dream of a year ago, life on the outside has held many frustrations, from bills coming due to promises not kept. Bitterness lingers with Patterson like a bad taste.
"They took 17 years out of my life," he said. "I should get at least 17 years of anger."
He steers his silver Mazda van past rusted, shuttered steel mills on the city's far South Side, toward a weathered frame house.
"That's the place that got me 17 years," he said.
It's the home where an elderly couple who allegedly fenced stolen goods were stabbed 34 times in 1986 -- a double murder that put Patterson on death row.
This block, like so many in the neighborhood, is filled with memories. Patterson, now 39, points out the Catholic school that he attended, the church where he was an altar server, the field where he played Little League.
The son of a police lieutenant and a schoolteacher, Patterson was groomed for success. He was a trophy-winning athlete and a graduate of good schools. He seemed destined to take the college-career-family path.
He enlisted in the National Guard, took the police exam, enrolled in the University of Illinois.
But he preferred being in a gang.
"I'd seen the street life ... and then I'd seen the side that's supposed to be law-abiding citizens, and I didn't see the difference," he offered as an explanation. "I just didn't respect the status quo."
As a leader of the Apache Rangers, Patterson beat people up, sometimes viciously. He soon had a long rap sheet for gang activities that included attempted murder.
"I just didn't turn the other cheek," he now says.
His record and reputation made him a candidate for questioning in the double murder.
But what happened in a police interrogation room would be scrutinized for the next 17 years -- and continues to be debated today despite Patterson's pardon.
The man in charge of Area 2's violent crimes unit was Lt. Jon Burge, a beefy cop with a menacing reputation who was fired in 1993 after investigators determined that he had used excessive force to squeeze a confession from a suspect.
Burge's critics claim that he also wired suspects to a device called a "Tucker telephone" and cranked electric shocks into them. They allege that he and other police officers beat suspects, subjected them to mock Russian roulette and chained them to hot radiators.
A report by a police investigatory agency in 1990 found that "abuse did occur and that it was systematic" at Area 2. A special prosecution team is investigating accusations from about 90 people who have directly or indirectly alleged brutality by Burge or officers working with him.
Burge, who has moved to Florida, has denied torturing anyone. He has not been charged.
Patterson claims that during 25 hours of questioning, police cuffed him to the wall, turned off the lights, punched him in the chest and nearly smothered him by holding a plastic typewriter cover tightly over his face. When he wouldn't confess, police repeated the torture, he says.
Between grillings, he claims, Burge came in, placed his gun on the table and warned him that if he didn't cooperate, he'd get something far worse.
Patterson says he was determined to leave a record if he were killed and, when left alone during one break, he used a paper clip and crudely scrawled a message on a metal bench.
"I lie about murders," it said. "Police threaten me with violence. Slapped and suffocated me with plastic. No lawyer or dad. No phone.... Aaron."
He never signed a statement, but prosecutors said they had an oral confession.
A jury convicted him. He was on his way to death row.
Jo Ann Patterson believed that her son was innocent and expected that the courts would straighten everything out.
Aaron's father, Raymond, she says, even appealed to his superiors in the police brass.
"My husband tried to get some help from his commander," she recalled. "He said, 'You might as well admit it. You've got a bad kid.' "
Aaron Patterson never gave up hope that he'd be released.
"I had this ongoing battle with God," he recalled. "It was like, 'Hey, look, I didn't do this.... Are you trying to give me a message or something? If you are, I hear you.' "
The years passed like a dripping faucet. Two years. Five. Ten.
"I said, hey, you took all my 20s," Patterson said. "Now you're going to take all my 30s?"
When one appeal after another failed, Patterson turned to his mother, who had separated from her husband.
"I said the system ain't going to correct itself," he said. "We've got to get out there and publicize my case."
She became his voice; he planned strategy. Inside his cell, he designed a leaflet telling his story. He organized rallies on his birthday with his mother standing vigil outside the prison.
He coached her: "Don't get out there and start crying. Don't do what they want you to do. Put the facts out there. They'll carry themselves."
She memorized the details of his case.
There was no physical evidence against him. Fingerprints in the couple's house did not belong to Patterson. And a girl who originally said he admitted the killings to her recanted.
Patterson's mother, a gentle woman who never sought the spotlight, began speaking to anti-death penalty groups, college students and any reporter who would listen. She traveled as far as Ireland to tell her son's story.
Amnesty International took an interest. Supporters formed a committee to publicize his case, a Web site was created, signatures were gathered on petitions in the United States and Europe.
Sometimes, Jo Ann Patterson would return from a speaking engagement to hear a critique from her outspoken son.
"I got mad," she recalled. "I said, 'You come out here and do it. It's not as easy as you think.' "
Patterson could annoy even his supporters.
"There were people who were thinking he was too aggressive and over the top," said Chris Bergin, a friend who worked on Patterson's committee. "But how do you make yourself stand out among so many men? He sure did that."
In prison, meanwhile, Patterson was known as a troublemaker. He threw food. Hot water. Even feces. He ended up spending most of his time behind bars in segregation, yet managed to phone reporters from there.
"I push the envelope all the time," he said. "If you don't ... nothing is going to change."
In early 2000, then-Gov. George Ryan declared a moratorium on the death penalty after 13 men on Illinois' death row were found to have been wrongly convicted.
The death penalty system was about to be placed under a microscope.
It was Patterson's big chance.
Last January, the big day came.
Days before leaving office, Ryan cleared out death row. He commuted to life terms the death sentences of 167 inmates, calling the state's capital punishment system arbitrary and immoral.
For Patterson and three other condemned men, the governor went a step further.
Ryan said a "manifest injustice" had occurred in their cases because police tortured the four into confessing to crimes they didn't commit.
Grateful as he is, Patterson isn't inclined to wipe the slate clean.
"They got the wrong guy if they think I'm going to say ... 'I just want to get on with my life. I don't hold any ill will toward the people who did that to me,' " he said.
He recently filed a $30-million federal lawsuit against police officers and others involved in his case. Lawyers for the defendants have declined comment.
Since his release, Patterson has joined picket lines for Latino workers and protests by public housing residents, spoken at a rally against the Iraq war, lobbied to get inmates' innocence claims investigated and testified before committees studying the death penalty.
In July, he witnessed the signing of a new state law that requires the audio or videotaping of murder interrogations and confessions -- the crux of the case against Patterson.
Afterward, he smiled, rubbed the document between his thumb and forefinger and said:
"I just have to touch this."
Aaron Patterson entered prison barely out of his teens and re-entered society approaching middle age.
Starting over has been a time of adjustment.
His mother noticed that her son had a habit of yelling to her from the back of the house -- something she suspected stems from his long years in a cell.
Patterson has a girlfriend and has dabbled in a few projects, including investing $5,000 to start a landscaping and snow-removal business.
He spent a large chunk of the $161,000 state compensation for his wrongful incarceration repaying a loan that he had taken out to bail out a friend whose murder conviction was overturned.
He then took out a second loan, he said, so "I can survive."
He keeps on the move, rejecting suggestions to return to college or find a job in the 9-to-5 world.
"I just don't have the patience," he said. "I've been sitting for 17 years."