Peoria County Coroner Johnna Ingersoll said an autopsy Saturday showed Carnell Ashford died of a fatal gunshot to the chest.
Ashford was found dead Friday after a passerby noticed the body in an alley behind a vacant house at 1404 N.E Perry Avenue.
Family members say Ashford had been living in Peoria for as long as a year, but his driver's license showed a Chicago address.
Two other people are believed to have been injured in the same shooting.
Anyone with information is asked to call Crimestoppers