A member of Kasselia's congregation, 29-year-old Salim Iskef, was among those murdered in Orebro on Tuesday in Sweden's first school shooting and the worst mass shooting in the country's history. The gunman killed 10 students at an adult learning centre and then himself.

Officials in Sweden have vowed to determine why a man killed 10 people, and apparently himself, in an unprecedented attack that's shaken their "society to its core."