According to SVT, the suspect, born in 2010, was arrested at lunchtime on Wednesday and has been remanded in custody.
The detention hearing will be held at Norrköping District Court on Friday afternoon.
A man in his 20s was shot in Norrköping on Walpurgis Eve. He later died from his injuries.
On May 4, two teenage boys were arrested on probable cause on suspicion of murder and aggravated weapons offenses. In connection with this, a person under 15 was taken into custody by social services on suspicion of involvement. Another teenager under 18 was arrested on May 8.
