Another man was ultimately convicted for the crimes after fingerprint evidence surfaced.
Tillman says over three days in police custody he was beaten with a phone book, punched in the face and threatened with execution until he confessed. He was convicted in 1986 largely on the basis of that confession.
Thursday prosecutors dropped all charges and a judge ordered Tillman to be set free.
Those who handle these wrongful conviction cases say it was the first time anyone affiliated with the Cook County State's Attorney's Office has ever admitted in open court that there was systematic torture of suspects by Chicago police officers.
For Michael Tillman that admission comes 23 and a half years too late.
Michael Tillman was scheduled to spend the rest of his life in prison. Thursday, he walked out of the Cook County Courthouse. There was no apology from prosecutors, but an admission that police torture led to the most damming piece of evidence against him: a confession.
"It felt good and I'm glad justice finally prevailed. I just want to thank everybody," said Tillman.
"He was tortured for three days. He was subjected to suffocation by a bag over his head. He was subjected to a mock execution with a gun at a remote site. He was waterboarded before we knew what that term meant," said Flint Taylor, Tillman's attorney, People's Law Office.
Tillman was twice convicted - first at a bench trial then by jury - of the 1986 rape and murder of Betty Howard. She lived in this high-rise where Tillman worked as a janitor.
The case was investigated by detectives under the command of Jon Burge.
In a court filing Thursday, the special prosecutor assigned to re-examine Tillman's case wrote the actions of police back then were "pursuant to a systematic pattern and practice of torture and abuse."
"It's the first time that's ever been said," said Taylor.
"It's hard when nobody seems to believe you. We just stayed in prayer. That's what you do. I know my brother did not do this," said Elizabeth MacGowan, Tillman's sister.
It's been said wrongful convictions yield two victims: In this case, Betty Howard and Michael Tillman. But Ms. Howard's family is not buying it.
"I will die goes to my grave feeling like this: Michael Tillman was the ring leader of this crime," said Angelita Howard, murder victim's daughter.
Tillman's attorneys say they plan to ask a judge for a formal "certificate of innocence" for their client and may sue the city and others. For now, Tillman hopes to begin catching up on 23-years lost behind bars.
"A little bit. But I got family so I'll be alright," said Tillman when asked if he's worried about transitioning into society. "I gotta get used to society all over again."
Years after Michael Tillman's conviction, police arrested and charged Clarence Trotter with Betty Howard's murder. They found her property in his possession and his fingerprints at the crime scene. Trotter will continue to serve a life sentence.
There are dozens of other people who remain behind bars claiming police torture played a role in their convictions.