At the Lloyd Gymnasium in Bremerhaven, a high school, an amok alarm was triggered on Thursday morning.
A woman was seriously injured, but not in mortal danger, said a press spokesman for the city of the FAZ. The woman was an employee of the school administration.
The authorities are not yet aware of any other victims.
The alleged perpetrator was arrested by the police shortly after the crime near the school.
It is a young man.
Reinhard Bingener
Political correspondent for Lower Saxony, Saxony-Anhalt and Bremen based in Hanover.
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Philipp Johannssen
Editor on duty at FAZ.NET.
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A video shows a man dressed in black standing at a crossroads near the school with a larger weapon lying next to him.
Before the emergency services arrive, the man lies down on the ground and quietly holds his hands behind his back, as if he is willing to be arrested.
The passers-by on the busy street were obviously not aware of the danger.
One man even wiggles his foot on the weapon, which appears to be a crossbow.
The information about the murder weapon was initially contradictory.
Loud shots were first reported from the school.
According to the authorities, the perpetrator used a crossbow.
Information about other weapons is currently not available.
A photo showing an arrow in a house wall also speaks in favor of using a crossbow.
The wall is on the other side of the intersection where the perpetrator was arrested.
After the crime, the police searched the Lloyd Gymnasium in large numbers to rule out the involvement of other perpetrators and asked the population to avoid Mayor Martin Donandt Square and the adjacent streets.
Shortly after the crime, there were rumors in the city about a second perpetrator or even a group of perpetrators.
The authorities are now assuming a single perpetrator.
The students had been warned of an amok situation after the attack on the high school staff.
An alarm was triggered over the loudspeaker with the code word "Mr. Koma" - "Koma" read backwards means "Amok".
The students and teachers then barricaded themselves in their rooms, and armed police officers secured the rooms.