A Chicago man who spent 32 years behind bars before DNA evidence helped overturn his conviction has been freed.

Andre Davis was wrongly convicted of the rape and murder of a three-year-old girl decades ago.

The Illinois Department of Corrections says 50-year-old left the super-maximum security prison in Tamms in far southern Illinois around 7.30pm on Friday, just hours after the local state's attorney agreed to drop the case against him.

An Illinois appeals court ordered a new trial in March. Tests found that DNA taken from the scene of the 1980 killing of Brianna Stickle in Rantoul was not his.

According to the Centre on Wrongful Convictions at Northwestern University, Mr Davis is among 42 former inmates who have been exonerated by DNA evidence in Illinois - and he served the most time behind bars.