HIGHLAND PARK, Ill. (AP) — For many people, the mass shooting that killed at least seven people and injured 30 others in a Chicago suburb on July 4 was yet another reminder that any place, any event in the U.S. can turn dangerous or deadly. Highland Park is one of the country’s safest towns, and July 4th parades among the most American of celebrations. Even before Monday’s killings, some people already were on edge, questioning whether to venture into large gatherings, looking over their shoulders during even the most run-of-the-mill activities, from grocery shopping to going to school or catching a movie.