“It can’t go on like this. Ebertplatz has been a trouble spot for a long time. The most recent incidents are a horrible proof of what the police have been saying – they can’t solve this problem alone,” said Andreas Hupke, mayor of the Innenstadt district, according to the Express newspaper.

Hupke, a politician for the Green party, was speaking after a 22-year-old man was stabbed to death on the square on Saturday evening.

He accused the police of focusing too much of their resources on the area around the Cologne central station, where mass sexual assaults took place against woman during New Year celebrations two years ago.

But he said that while the central station was now calm, “the police have given up control of Ebertplatz.”

“If nothing changes there, this won’t be the last time something like this happens,” he warned.

Police arrested three men on suspicion of murdering the man and are searching for a further suspect. The square, which connects three inner-city neighbourhoods, is known as a hot spot for drug dealing in the Rhine city, according to Express.

This is the second time this month that a mayor from the Greens – a liberal, environmentalist party – has accused police of giving up control of a central area of their city.

Earlier in October, Stephan von Dassel, the mayor of the Berlin neighbourhood of Mitte, said the Tiergarten park had turned into a “zone of illegality”.

He called on the police to up their presence in the famous green space after a woman was murdered on her way home from a night out.

The number of murders in Germany has steadily declined since the start of the century. Nonetheless, in 2016 the number of murder victims rose by 26 percent to 373 in comparison with the previous year. That was the highest recorded number of murder victims in over a decade.

READ MORE: How a murder has forced light into the shadows of Berlin's ‘lawless' central park