A shooter fired on an Independence Day parade from a rooftop in suburban Chicago, spraying the crowd with gunshots initially mistaken for fireworks before hundreds of panicked revelers of all ages fled in terror. At least six people were killed and at least 30 wounded.

An hourslong manhunt during which residents hunkered down in businesses or received police escorts to their homes ended with a traffic stop and brief chase Monday evening, when authorities detained a man they described as a person of interest. They gave no motive for the attack in Highland Park, an affluent community of about 30,000 on Chicago’s north shore.

The July 4 shooting was just the latest to shatter the rituals of American life. Schools, churches, grocery stores and now community parades have all become killing grounds in recent months. This time, the bloodshed came as the nation tried to find cause to celebrate its founding and the bonds that still hold it together.

“It definitely hits a lot harder when it’s not only your hometown but it’s also right in front of you,” resident Ron Tuazon said as he and a friend returned to the parade route Monday evening to retrieve chairs, blankets and a child’s bike that he and his family abandoned when the shooting began.

“It’s commonplace now,” Tuazon said. “We don’t blink anymore. Until laws change, it’s going to be more of the same.”