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.

Police believe the suspected killer - identified by a Reuters source and Swedish media as Rickard Andersson, a 35-year-old unemployed recluse - acted alone in Tuesday's attack on an educational campus in Orebro. Authorities said the gunman may have attended at the Risbergska adult education centre, west of Stockholm.

Sweden on Wednesday was recovering from the deadliest mass shooting in its history after 10 people -- as well as the suspected gunman -- were killed at an education centre in the city of Orebro, with many questions still unanswered.