Last week, a 26-year-old man from Amsterdam was arrested. He may have lent his car to the other suspects. This man has since been released but remains part of the ongoing investigation.

The shooter, a 15-year-old boy from Hoorn, was previously convicted by the German court. The Dutch police are investigating possible Dutch involvement, with suspicion that they persuaded and/or facilitated the convicted boy in committing the shooting incident.

The police continue the investigation and do not rule out further arrests.