Three women and one man were injured in the incident on Friday, before other students managed to restrain the attacker at the Hamm-Lippstadt University of Applied Sciences.

The 34-year-old suspect, who had been armed with two kitchen knives, “randomly selected” the victims, Dortmund prosecutors’ office spokesman Henner Kruse told reporters.

A 30-year-old assistant professor who was among those attacked while attending a conference was in hospital in a critical condition and doctors feared the worst. 

A 22-year-old student had suffered eight stab wounds to the stomach and needed emergency surgery, but her condition was not life threatening.

The other two victims, a 22-year-old man and another young woman of the same age, were less seriously injured, he added.

The suspect, a student at the university in the western German city of Hamm, said after the attack that he had felt threatened by a group of students who, according to him, wanted to “annihilate him”.

He was possibly suffering from “paranoid schizophrenia” and “hallucinations”, Kruse said, adding that he had a long history of treatment for mental health problems.

The police had ruled out any political or religious motives for the attack and an investigation for attempted murder and serious injury had been opened against him.

The WDR broadcaster, has reported that the suspect released himself from a psychiatric ward shortly before the stabbings, where he had been treated after a suicide attempt. He was in the psychiatric ward voluntarily because of self-harm and not by force or by a police order.

On Friday, the Ham police force wrote on Twitter that they were conducting a “major operation” in the area of the Hamm-Lippstadt University of Applied Sciences, asking people to avoid the area. The Dortmund police force have since taken over the investigation.

Die #Polizei #Hamm hat einen größeren Einsatz im Bereich der Hochschule Hamm-Lippstadt. Mehrere Personen wurden mit einem Messer verletzt. Der Täter ist sicher. Wir sind mit starken Polizeikräften vor Ort und bitten Sie, diesen Bereich zu meiden. Wir berichten hier.

— Polizei NRW HAM (@polizei_nrw_ham) June 10, 2022

According to the WDR broadcaster, the 34-year-old suspect went into the university building around 3:30pm on Friday. He attacked students with a knife in the corridors and then headed for a larger lecture hall with a lecture in progress, where students managed to restrain him. 

The first emergency services were on site just three minutes after the first emergency calls. Students held the suspect until the police arrived, WDR reported.

It is unclear whether the university will open as usual on Monday.

“We can’t imagine going back to normal standard operations on Monday. That wouldn’t be appropriate either,” the chancellor of the university, Sandra Schlösser, told WDR.