The 55-year-old man, identified by the Cook County medical examiner's office as Alfons Dzieszuta of the 100 block of Bonnie Brae avenue in Mt. Prospect, fell off the roof of the building in the 4400 block of North Bernard Street about 5 p.m., said Chicago Police Department News Affairs Officer Amina Greer. The man was believed to have been working on the building's roof, officials said.