The preliminary investigation has been reclassified as attempted murder, attempted gross public devastation and attempted gross violation of the Act on Flammable and Explosive Goods, police wrote on their website.
Earlier on Wednesday evening, police cordoned off an area in Södermalm in Stockholm after a suspected dangerous object was found in a pub.
The object was thrown in without exploding, according to police spokesman Robert Sennerdal. National bomb disposal technicians were called to the scene.
There were guests at the restaurant, but everyone got out and no one was injured.
The alarm about the suspicious object came shortly after 9 p.m.
