The man suspected of aggravated assault was arrested at Kalmar District Court on Tuesday.
He is the fifth young man to be arrested after a 25-year-old was stabbed to death the night of Walpurgis Night.
Two men are already in custody on suspicion of murder, two are suspected of aggravated assault.
Wanted before
The 18-year-old, who is a resident of Kronoberg County, has previously been wanted by the police.
On Friday night, he was found by a police patrol in Växjö center, states Smålandsposten.
The prosecutor wanted the man arrested on suspicion of murder, but the district court chose the alternative suspicion of aggravated assault.
The background to the incident must have been "two constellations" that got into a fight with each other, and which ended with a person being stabbed to death, prosecutor Johan Henningsson has previously told SVT.
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Kalmar resident Josefin Hedstrand talks about how it feels to see when a murder takes place right outside her apartment.
Photo: Hamed Ubaidi-Karlsson