Three young men were stabbed by a still unknown perpetrator on Carnival Sunday in Düsseldorf's old town.
A 17-year-old victim was still in mortal danger on Monday, a police spokeswoman said.
A homicide detective is investigating.
Accordingly, there was an argument between two previously unknown men and a group of people on Sunday at Burgplatz am Rhein.
One of the two men stabbed a seventeen-year-old, an eighteen-year-old and a twenty-two-year-old.
Then the main suspect and his companion fled.
All three victims underwent emergency surgery, and the life of the eighteen-year-old was also initially in danger.
According to investigators, the suspects, who were not dressed up for the carnival, were caught on a police surveillance camera.