Aug. 30 (UPI) — Authorities in Switzerland said a manhunt is underway for one or more suspects following a shooting at a rave that killed a woman and wounded five other people on Sunday.

“The manhunt for the unknown perpetrator is underway,” the Aargau cantonal police said in a statement. “The possible motives as well as the exact circumstances of the crime are still unclear.”

The police force said the shooting occurred early Sunday during a rave in the Schachen neighborhood of Aarau, the capital of Switzerland’s northern Aargau canton.

A 22-year-old woman was killed and four men and a woman between the ages of 24 and 27 were shot and taken to the hospital where they were assessed for injuries ranging from minor to severe, police said. All victims are residents of Switzerland.

The deceased was identified as Italian citizen Maria Spinelli by Italian Prime Minister Giorgia Meloni. Italy’s Ministry of Foreign Affairs said two people who suffered minor injuries in the shooting were also Italian citizens and have since returned home.

“The Italian Task Force … is working to assist the families of the Italians involved in last night’s rave shooting and to closely follow developments and the investigation, in coordination with the Swiss authorities,” the ministry said in a statement.

Police Chief Michael Leupold told reporters at a press conference that they are investigating the crime, though investigators are unsure if it was a terrorist attack, a rampage shooting or a criminal act with some other motive.

Shell casings retrieved from the scene indicate two weapons were used, a handgun or submachine gun and a large weapon, such as a possible assault rifle, police said.

The cantonal government said in a statement that it was “deeply shocked” by the violence, saying, “Its thoughts are with the victims, their families and all those who had to witness this terrible event.”