In a ruling Thursday, justices say Stanley Wrice should be appointed counsel and that his post-conviction case should continue.
Prosecutors had tried to block the case from continuing, arguing that they had enough evidence to convict Wrice even without the confession.
Wrice says officers working for convicted police Lt. Jon Burge used a flashlight and rubber hose to beat him in the face and groin until he confessed to a 1982 sexual assault that he didn't commit.
He was convicted in 1983 and is serving a 100-year sentence.
Burge is serving a 4 1/2-year sentence for perjury and obstruction of justice.
