A police union even blamed the complicated laws which regulate the lives of those without work for the attack in Neuss, near Düsseldorf.

“When it concerns someone’s existence, then sudden, irrational actions fuelled by anger and desperation are anything other than unforeseeable,” said Erich Rettinghaus, chairman of the North Rhine-Westphalia DPolG police union.

The 52-year-old man entered the 32-year-old woman’s office without an appointment at about 9am on Wednesday. There were no witnesses to the conversation but she was stabbed so badly with a knife that she died shortly afterwards, despite the first-aid efforts of her colleagues, the Düsseldorf state prosecutor said.

The alleged attacker was arrested shortly afterwards nearby. He and the dead woman did not have a personal relationship, the prosecutor said.

Initial investigation suggested she had not activated the special emergency button on her computer keyboard which would have alerted colleagues that she was in trouble.

The fact that such a system exists and that she had been on a de-escalation course just a day before she died, demonstrates the problems with violence at job centres and efforts to prevent attacks.

“Nothing, absolutely nothing justifies such actions,” said Heinrich Alt, member of the Labour Agency board. But he added that “our staff cannot lock themselves away behind bullet-proof glass. We need to work on a trust basis with our clients. And for this we have to remain an open authority.”

The job centre will remain closed until the end of the week. At least 15 people who witnessed the consequences of the attack were treated on the scene for shock.

A police murder squad has taken over the investigation.

DAPD/The Local/hc