BERLIN (AP) — A school employee was seriously wounded in an attack Thursday at a high school in the northern German city of Bremerhaven and a suspect was detained, investigators said.

Police said they were alerted at 9:15 a.m. to someone having entered the Lloyd High School in the port city and wounding one person with a weapon that they didn’t identify.

They said the suspect, a 21-year-old man, was detained near the school shortly afterward without putting up resistance. Students stayed in classrooms while police searched the building. They were evacuated around lunchtime after investigators determined there were no other perpetrators on the premises.

The wounded woman was taken to a hospital and her life was still in danger, prosecutor Oliver Constien said.

The investigation so far indicates that “a particular psychological disposition may have contributed” to the attack, he added. He said investigators would work to determine whether the suspect knew the victim. There was no immediate word on a possible motive.

About 200 students were at the school and final exams had been scheduled, the German news agency dpa reported. It wasn’t immediately clear how many teachers and other employees were on the premises at the time.