A shooting occurred in the early hours of Sunday at a techno party held at a covered horse-racing track in the northern Swiss town of Aarau, west of Zurich. Around 3,500 people attended the event. Several shots were fired at a group of people just as partygoers were preparing to go home. Some attendees initially mistook the gunshots for fireworks until someone shouted for everyone to get down.
The attack left a 22-year-old Italian woman dead at the scene. Five other people, four men and one woman between the ages of 24 and 31, were taken to the hospital with injuries ranging from minor to severe. All those caught up in the shooting were residents of Switzerland in their 20s.
Authorities launched a large-scale police operation in the area, urging residents to stay away and appealing for photos or videos from witnesses. While a manhunt was initially underway for unknown perpetrators, police announced on Monday that they had arrested a 43-year-old Swiss citizen.
Police believe a lone gunman was involved in the incident. Although gun ownership is relatively widespread in the Alpine country, public shootings are rare. Investigations into the deadly shooting are ongoing.