"My thoughts are primarily on the victim, his family, friends and teammates," Strömmer said in a written comment.
One police theory is that the 20-year-old, who played for a local football club, was not the intended target because investigators have found no connection between him and criminal groups.
"The police are working intensively to find out what happened and identify the person or persons behind this. And as a society, we must not slow down in the work against serious violence," said Strömmer.
