An 18-year-old suspect carried out a sword attack at Brinell School in Fagersta, Sweden, killing a 17-year-old student and injuring three others.

Two of the injured, ages 12 and 17, were seriously wounded, while a third person under 18 suffered minor injuries.

Police arrested the suspect and are investigating the incident as murder and attempted murder, with no indication that another attacker was involved.

Authorities have not identified a motive and are interviewing witnesses, reviewing camera footage, and conducting searches connected to the suspect, CBS News has reported.

The attack has renewed concerns about school violence in Sweden, which has experienced several deadly school attacks in recent years.