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."

Sweden's worst mass shooting left at least 11 people dead, including the gunman, and at least five seriously wounded at an adult education center west of Stockholm. The gunman's motive hadn't been determined by early Wednesday as the Scandinavian nation — where gun violence at schools is very rare — reeled from an attack.

The suspect, named in reports as 35-year-old local man Rickard Andersson, was reported to be a former student of the school in Orebo, a city 157 km (98 miles) west of Stockholm, where the attack took place on Tuesday. Eleven people died in the shooting, including the attacker, with at least six others injured.

Despite his gunshot wounds, sustained Tuesday in Sweden's deadliest mass shooting, Salim Karim Iskef managed to video-call his fiancee to tell her he loved her one last time. The 28-year-old asked Kareen Alia to look after his mother and herself before the call ended.

Swedish police said the gunman in the country’s worst mass shooting was connected to the adult education center where he opened fire Tuesday, killing 10 other people

"But this hate, it is coming from somewhere." 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.