Swiss police say they arrested a 43-year-old man on Monday after a deadly shooting at a rave in northern Switzerland led to the death of an Italian citizen and saw several other young people wounded.

Aargau Cantonal Police previously said one person was killed and five others were wounded after shots were fired at the event in the town of Aarau, a scenic area known for its lush valleys, medieval castles and thermal springs.

“Investigations into the exact sequence of events, as well as the background and possible motive, are currently underway. At this stage, it is assumed there was a single perpetrator,” the police said in an update following the suspect’s arrest.

A 22-year-old woman died at the scene, police said, while four men and one woman, aged 24 to 27, are being treated in hospital for injuries ranging from minor to severe.

All of the victims held Swiss residency, police said.

Italian Prime Minister Giorgia Meloni later named the victim as Maria Spinelli.

“My thoughts also go to the other injured, including two Italian citizens, and to all those involved in this dramatic incident,” she said in a statement, adding they trust Swiss authorities to “shed full light on the incident and identify those responsible.”

The shooting happened at the Schachen horse racing track in the town, police said. A rave was being held at the venue at the time, according to social media posts from the event organizers.

The shooter’s motive and the exact circumstances of the incident remain unclear, police said.

Swiss DJ Tekibo, who played at the rave, took to his Instagram to write a statement describing the incident as “heartbreaking.”

“Techno and raves should be places of freedom and safety, never places where something like this happens,” he wrote. The DJ added that he “lost an important friend,” without elaborating.Aarau

Speaking to Swiss news outlet Blick, one eyewitness said he initially thought the gunshots were fireworks.

“At 2:30 a.m. the music suddenly stopped, and after a minute or two I suddenly heard the gunshots…I thought it was fireworks and didn’t think anything of it,” he was cited as saying.

As he walked across an open yard, he recalled hearing a shot ring out and seeing that a woman had been hit. Despite attempts to save her, she succumbed to her injuries, the eyewitness told Blick.

A large area around the venue has been cordoned off, and police have asked members of the public to stay away from the area.

Switzerland has one of the highest rates of gun ownership in Europe, although shootings are rare. In 2019, Swiss voters approved tighter gun control rules in a national referendum.

Switzerland’s deadliest mass shooting occurred in 2001, when a gunman killed 14 politicians in what became known as the Zug massacre. (CNN)