Aarau canton police confirmed they apprehended a suspect shortly before 01:00 on Monday (23:00 GMT on Sunday) following a nearly 24-hour manhunt after a shooting at a techno rave in Switzerland on Sunday.

The arrest comes after Maria Spinelli, a 22-year-old Italian woman, was killed and several others injured at a rave being held at a horse racing track in Aarau, a town about 46km (29 miles) west of Zurich. The shooting initiated the manhunt, which lasted for nearly 24 hours before police confirmed they had apprehended the suspect.

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"The investigation into the exact sequence of events, the background, and the possible motive is currently underway," said Aarau canton police in a statement. "At this time, it is assumed that the perpetrator acted alone." The investigation is ongoing, with police working to determine the exact cause of the shooting.

Police first received a report of shots fired at the Schachen race track at about 02:30 local time (00:30 GMT) on Sunday. Spinelli died at the scene, while four men and a woman, aged between 24 and 27, were taken to hospital with injuries "ranging from minor to severe".

An eyewitness told Swiss media outlet Blick that he "suddenly heard the gunshots" minutes after the music stopped, initially believing they were fireworks. He was told to hide and did not witness the shooting.

Organisers had expected 3,500 people to attend, but the event was attended Aarau, home to approximately 23,000 people, is less than 40km from the border with Germany, where local media reported police were supporting Swiss forces. Italy's prime minister Giorgia Meloni previously said she was confident Swiss authorities would "shed full light on what happened and find anyone responsible".

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Italy's foreign ministry said in a statement it was sending officials to Zurich "to closely follow the investigation". Switzerland has one of the highest rates of gun ownership in Europe, although violent shootings are rare and tighter controls were introduced in recent years.

The last major shooting occurred in 2001, when 14 members of the parliament and local government of Zug, near Lucerne, were killed.