The two teenage boys have been detained on probable cause on suspicion of murder and aggravated weapons offenses, Norrköping District Court announced.
"I believe that this is strong evidence and that the investigation going forward will hopefully strengthen it as well," Deputy Chief Prosecutor Karin Sandén said.
One of the boys admits involvement in the murder through his lawyer, but claims self-defense as he acted under threat, Norrköping's newspapers reported.
The other boy denies the crime.
According to P4 Östergötland, another person is suspected of involvement in the murder in which a man in his 20s was shot and later died of his injuries.
The two teenagers are also suspected of a murder in the Oslo area last weekend. The victim in Norway was a man in his 20s who, according to Norwegian police, was linked to criminal circles.
