German media write that the victim is a female employee of this school, the Lloyd Gymnasium. The person is in a hospital. The suspect has been taken to the police station.
The school has been combed to rule out the presence of any other perpetrators. Some students are said to have holed up in their classrooms. The media also report that about two hundred children were at school, less than usual because tests were taken. The school has a total of about 1700 students.
The police reported late in the morning that students and teachers were in their classrooms and the situation is under control. The first attendees were allowed to leave the building around 12.20 pm, according to the German news site Nord24.