Emin Muqa Kulic, a leading figure in the Swedish gang Dalennätverket, was extradited from Spain and detained on numerous charges including attempted murder and weapons offenses.
Authorities investigate youths linked to the Fagersta school attack, including a 15-year-old girl suspected of murder preparation and others held on related charges.
Two suspects deny charges as Swedish police conduct hundreds of interrogations in a complex investigation following the deadly Fagersta school attack.
Authorities have arrested a second suspect suspected of aiding in the Fagersta school attack, while the main assailant remains in custody as investigations and legal proceedings continue.
The Rättvik bombing trial is paused for a forensic psychiatric evaluation of the 18-year-old suspect, with the trial resuming in July amid serious attempted murder charges.