Six of the detainees are suspected of murder and two are suspected of preparing for murder.
They were all arrested on Monday morning just hours after the fatal shooting.
According to information to SVT, several of the arrested persons can be linked to the so-called Death Patrol, a criminal gang that recently published in the Danish Ekstrabladet that they had allied themselves with the gang banned in Denmark Loyal To Familia.
Young men from the area
The detainees are between 18-28 years old and several live near the crime scene.
The majority have been convicted of several crimes in the past, such as drug offenses and violence against civil servants.
Carl Mellberg, who is the prosecutor and responsible for the investigation, cannot comment on any details of the police's work.
He has until 12 o'clock on Thursday to decide whether to request the suspects detained or release them.
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GANG VIOLENCE: "Best friends one day, enemies the next" Photo: SVT