The alarm was raised around 23:00 Saturday night about a dispute on Bredgatan in the southern Swedish city. When police arrived they found several people injured, and one person who was pronounced dead at the scene.
Along with the fatality, a further man suffered serious stabbing injuries and a third suffered minor stabbing injuries. All three are aged between 19 and 24.
On Sunday police said that three youngsters had been arrested. One, a 17-year-old, is suspected of murder. He is also thought to have used a weapon on all three people hurt in the altercation and is therefore additionally suspected of two counts of attempted murder.
Two further men were arrested later on Sunday, each suspected of attempted murder.
“I can't say more than that it's two men in their twenties, who are acquainted with the first person arrested,” Tommy Lindén from Helsingborg police told news agency TT.
Police are working to establish how the suspects know the victims:
“We don't have a good picture of how this started and what happened. That will come during the week”.
According to witnesses, between seven and eight people were involved in the dispute, but police have not yet confirmed the number.