A 22-year-old woman, Maria Spinelli, was killed in a shooting at a rave in Switzerland overnight. Police have arrested a 43-year-old man in connection with the incident. Authorities believe the suspect acted alone in the shooting. Before the incident, Spinelli reportedly sent a message to her mother stating she was with friends. The cantonal police are continuing their investigation to determine the motive behind the attack. This tragic event has shaken the rave community and prompted a police response to ensure future event safety.