Swiss authorities are conducting a nationwide search following a shooting that left one woman dead and five others wounded at a rave in Aarau, Switzerland, early Sunday. The incident occurred as an event with approximately 3,000 attendees was winding down at a horse-racing track in the northern part of the country.

Police have not confirmed how many suspects were involved, nor have they determined a motive for the attack. Col. Michael Leupold of the cantonal police stated Sunday evening that investigators are exploring multiple possibilities, including terrorism, a targeted criminal act, or another form of mass violence. “We are pursuing these three possibilities intensively; all three are equally likely based on the current state of investigation,” he said.

The deceased has been identified as a 22-year-old Italian woman residing in Switzerland. Among the injured are four men and one woman between the ages of 24 and 27, according to authorities. Initial reports that all victims were Swiss were revised following the identification of the fatality. The police said bullet casings recovered at the scene indicated the use of firearms with at least two different calibers—one likely from a handgun or small machine gun and the other from an automatic rifle.

Witness accounts varied, with some stating they saw two shooters, but officials have yet to verify this information. Security forces, including a special army unit and a helicopter, were deployed to assist in the search. Switzerland's defense structure, which includes a universal military draft and allows many trained men to keep service weapons at home, facilitated rapid deployment, although most are not permitted to store ammunition there.

Authorities emphasized that the risk to the public remains low, as they believe the suspect or suspects have fled the area. The search is ongoing throughout Switzerland.

In response to the attack, the rave organizers posted a message on Instagram, expressing sorrow and condemning the violence. Their statement described the shooting as a “cowardly attack” that shattered the spirit of the event, which they said should be a “place of joy and love.” Authorities continue to appeal for information from the public as the investigation progresses.