Swiss police declared on Monday that they had arrested a 43-year-old suspect in relation to a ‌deadly shooting at a rave in the town of Aarau on the weekend.

A 22-year-old Italian ​woman was killed and five ​people injured after the shooting at the event at a covered horse ​race track in the early hours of ⁠Sunday morning.

Police ⁠launched a ‌massive operation and just before 1 a.m. on Monday arrested a 43-year-old Swiss man on suspicion of carrying out the attack, ⁠it remarked.

In a related development, "Investigations into the exact circumstances of the incident, as well as its background ‌and possible motive, are currently underway. At this stage, it is assumed that a single perpetrator was involved," police in ​the canton of Aargau declared in a statement.

Police on ⁠Sunday noted they were investigating three possible motives ⁠for the shooting, including a mass ⁠shooting, ⁠an act ​of terrorism or an unknown criminal motive.

Cartridges found at ​the crime ⁠scene indicated two calibers of bullets, possibly from a pistol and a second, larger weapon, potentially an assault rifle, police expressed.