By MICHAEL TARM, KATHLEEN FOODY and ROGER SCHNEIDER A Lake Forest, Ill., police officer walks down Central Ave in Highland Park, Ill., on Monday, July 4, 2022, after a shooter fired on the northern suburb's Fourth of July parade. (Brian Cassella/Chicago Tribune via AP) A gunman on a rooftop opened fire on an Independence Day parade in suburban Chicago on Monday, killing at least six people, wounding at least 30