Blogs about the true back-story

http://blogs.chicagotribune.com/news_columnists_ezorn/2009/11/more-followup-on-call-northside-777.html

There is a suggestion that Vera Walush (Wanda Skutnik in the movie) feared retribution from the police if she recanted her story. Also,

Meanwhile, a detective informed Judge Charles P. Molthrop, who had presided over the case, that Majczek had been framed. Convinced now that justice had been miscarried, Molthrop accused Walush of perjury and vowed to push for a new trial "even if," he said, "I have to pay for it out of my own pocket." Molthrop, however, did nothing further allegedly because a prosecutor in the state's attorney's office told the judge that if he persisted in pursuing the case, his career would very quickly come to an end.