A 43-year-old Swiss man has been arrested following a shooting at a rave in Switzerland in which a woman was killed.

Italian 22-year-old Maria Spinelli was killed and several others injured at a techno rave being held at a horse racing track in Aarau, a town about 46km (29 miles) west of Zurich on Sunday.

The shooting initiated a nearly 24-hour manhunt before Aarau cantonal police confirmed they apprehended the suspect shortly before 01:00 local time on Monday (23:00 GMT on Sunday).

“The investigation into the exact sequence of events, the background and the possible motive is currently under way,” police said in a statement. “At this time, it is assumed that the perpetrator acted alone.”

Police first received a report of shots fired at the Schachen race track at about 02:30 local time 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 news outlet Blick that he had “suddenly heard the gunshots” minutes after the music stopped, initially believing they were fireworks.

He said he was told to hide by a man and a woman, the latter of whom was shot.

Organisers had expected 3,500 people to attend. 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.

The arrest marks a quick progression in the police investigation – on Sunday afternoon, the force in Aarau said it had no leads on the perpetrator and was unsure whether it was one person or several.

Italian Prime Minister Giorgia Meloni previously said she was confident Swiss authorities would “shed full light on what happened and find anyone responsible”.

Italy’s foreign ministry said in a statement that 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 by a gunman who then took his own life.